Novel insight into lepidopteran phylogenetics from the mitochondrial genome of the apple fruit moth of the family Argyresthiidae.

BACKGROUND: The order Lepidoptera has an abundance of species, including both agriculturally beneficial and detrimental insects. Molecular data has been used to investigate the phylogenetic relationships of major subdivisions in Lepidoptera, which has enhanced our understanding of the evolutionary relationships at the family and superfamily levels. However, the phylogenetic placement of many superfamilies and/or families in this order is still unknown. In this study, we determine the systematic status of the family Argyresthiidae within Lepidoptera and explore its phylogenetic affinities and implications for the evolution of the order. We describe the first mitochondrial (mt) genome from a member of Argyresthiidae, the apple fruit moth Argyresthia conjugella. The insect is an important pest on apples in Fennoscandia, as it switches hosts when the main host fails to produce crops. RESULTS: The mt genome of A. conjugella contains 16,044 bp and encodes all 37 genes commonly found in insect mt genomes, including 13 protein-coding genes (PCGs), two ribosomal RNAs, 22 transfer RNAs, and a large control region (1101 bp). The nucleotide composition was extremely AT-rich (82%). All detected PCGs (13) began with an ATN codon and terminated with a TAA stop codon, except the start codon in cox1 is ATT. All 22 tRNAs had cloverleaf secondary structures, except trnS1, where one of the dihydrouridine (DHU) arms is missing, reflecting potential differences in gene expression. When compared to the mt genomes of 507 other Lepidoptera representing 18 superfamilies and 42 families, phylogenomic analyses found that A. conjugella had the closest relationship with the Plutellidae family (Yponomeutoidea-super family). We also detected a sister relationship between Yponomeutoidea and the superfamily Tineidae. CONCLUSIONS: Our results underline the potential importance of mt genomes in comparative genomic analyses of Lepidoptera species and provide valuable evolutionary insight across the tree of Lepidoptera species.

Mitogenomics of the suborder Cottoidei (Teleostei: Perciformes): Improved assemblies, mitogenome features, phylogeny, and ecological implications.

We determined the mitogenome of Cyclopterus lumpus using a hybrid sequencing approach, and another four closely related species in the Liparidae based on available next-generation sequence data. We found that the mitogenome of C. lumpus was 17,266 bp in length, where the length and organisation were comparable to those reported for cottoids. However, we found a GC-homopolymer region in the intergenic space between tRNALeu2 and ND1 in liparids and cyclopterids. Phylogenetic reconstruction confirmed the monophyly of infraorders and firmly supported a sister-group relationship between Cyclopteridae and Liparidae. Purifying selection was the predominant force in the evolution of cottoid mitogenomes. There was significant evidence of relaxed selective pressures along the lineage of deep-sea fish, while selection was intensified in the freshwater lineage. Overall, our analysis provides a necessary expansion in the availability of mitogenomic sequences and sheds light on mitogenomic adaptation in Cottoidei fish inhabiting different aquatic environments.

Antimicrobial resistance-Do we share more than companionship with our dogs?

AIMS: To investigate and compare antimicrobial resistance genes (ARGs) in faeces from cohabiting dogs and owners. METHODS AND RESULTS: DNA from faecal samples from 35 dogs and 35 owners was screened for the presence of 34 clinically relevant ARGs using high throughput qPCR. In total, 24 and 25 different ARGs were present in the dog and owner groups, respectively. The households had a mean of 9.9 ARGs present, with dogs and owners sharing on average 3.3 ARGs. ARGs were shared significantly more in households with dogs over 6 years old (3.5, interquartile range 2.75-5.0) than in households with younger dogs (2.5, interquartile range 2.0-3.0) (p = 0.02). Dogs possessed significantly more mecA and aminoglycoside resistance genes than owners. CONCLUSIONS: Dogs and owners can act as reservoirs for a broad range of ARGs belonging to several antimicrobial resistance classes. A modest proportion of the same resistance genes were present in both dogs and owners simultaneously, indicating that ARG transmission between the dog and human gut is of minor concern in the absence of antimicrobial selection. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provides insight into the common dog and human gut resistomes, contributing to an improved knowledge base in risk assessments regarding ARG transmission between dogs and humans.

Sea ice reduction drives genetic differentiation among Barents Sea polar bears.

Loss of Arctic sea ice owing to climate change is predicted to reduce both genetic diversity and gene flow in ice-dependent species, with potentially negative consequences for their long-term viability. Here, we tested for the population-genetic impacts of reduced sea ice cover on the polar bear (Ursus maritimus) sampled across two decades (1995-2016) from the Svalbard Archipelago, Norway, an area that is affected by rapid sea ice loss in the Arctic Barents Sea. We analysed genetic variation at 22 microsatellite loci for 626 polar bears from four sampling areas within the archipelago. Our results revealed a 3-10% loss of genetic diversity across the study period, accompanied by a near 200% increase in genetic differentiation across regions. These effects may best be explained by a decrease in gene flow caused by habitat fragmentation owing to the loss of sea ice coverage, resulting in increased inbreeding of local polar bears within the focal sampling areas in the Svalbard Archipelago. This study illustrates the importance of genetic monitoring for developing adaptive management strategies for polar bears and other ice-dependent species.

Sociodemographic factors modulate the spatial response of brown bears to vacancies created by hunting.

There is a growing recognition of the importance of indirect effects from hunting on wildlife populations, e.g. social and behavioural changes due to harvest, which occur after the initial offtake. Nonetheless, little is known about how the removal of members of a population influences the spatial configuration of the survivors. We studied how surviving brown bears (Ursus arctos) used former home ranges that had belonged to casualties of the annual bear hunting season in southcentral Sweden (2007-2015). We used resource selection functions to explore the effects of the casualty's and survivor's sex, age and their pairwise genetic relatedness, population density and hunting intensity on survivors' spatial responses to vacated home ranges. We tested the competitive release hypothesis, whereby survivors that increase their use of a killed bear's home range are presumed to have been released from intraspecific competition. We found strong support for this hypothesis, as survivors of the same sex as the casualty consistently increased their use of its vacant home range. Patterns were less pronounced or absent when the survivor and casualty were of opposite sex. Genetic relatedness between the survivor and the casualty emerged as the most important factor explaining increased use of vacated male home ranges by males, with a stronger response from survivors of lower relatedness. Relatedness was also important for females, but it did not influence use following removal; female survivors used home ranges of higher related female casualties more, both before and after death. Spatial responses by survivors were further influenced by bear age, population density and hunting intensity. We have shown that survivors exhibit a spatial response to vacated home ranges caused by hunting casualties, even in nonterritorial species such as the brown bear. This spatial reorganization can have unintended consequences for population dynamics and interfere with management goals. Altogether, our results underscore the need to better understand the short- and long-term indirect effects of hunting on animal social structure and their resulting distribution in space.

Monitoring of the Apple Fruit Moth: Detection of Genetic Variation and Structure Applying a Novel Multiplex Set of 19 STR Markers.

The apple fruit moth Argyresthia conjugella (Lepidoptera, Yponomeutidae) is a seed predator of rowan (Sorbus aucuparia) and is distributed in Europe and Asia. In Fennoscandia (Finland, Norway and Sweden), rowan fruit production is low every 2-4 years, and apple (Malus domestica) functions as an alternative host, resulting in economic loss in apple crops in inter-mast years. We have used Illumina MiSeq sequencing to identify a set of 19 novel tetra-nucleotide short tandem repeats (STRs) in Argyresthia conjugella. Such motifs are recommended for genetic monitoring, which may help to determine the eco-evolutionary processes acting on this pest insect. The 19 STRs were optimized and amplified into five multiplex PCR reactions. We tested individuals collected from Norway and Sweden (n = 64), and detected very high genetic variation (average 13.6 alleles, He = 0.75) compared to most other Lepidoptera species studied so far. Spatial genetic differentiation was low and gene flow was high in the test populations, although two non-spatial clusters could be detected. We conclude that this set of genetic markers may be a useful resource for population genetic monitoring of this economical important insect species.

Brown and polar bear Y chromosomes reveal extensive male-biased gene flow within brother lineages.

Brown and polar bears have become prominent examples in phylogeography, but previous phylogeographic studies relied largely on maternally inherited mitochondrial DNA (mtDNA) or were geographically restricted. The male-specific Y chromosome, a natural counterpart to mtDNA, has remained underexplored. Although this paternally inherited chromosome is indispensable for comprehensive analyses of phylogeographic patterns, technical difficulties and low variability have hampered its application in most mammals. We developed 13 novel Y-chromosomal sequence and microsatellite markers from the polar bear genome and screened these in a broad geographic sample of 130 brown and polar bears. We also analyzed a 390-kb-long Y-chromosomal scaffold using sequencing data from published male ursine genomes. Y chromosome evidence support the emerging understanding that brown and polar bears started to diverge no later than the Middle Pleistocene. Contrary to mtDNA patterns, we found 1) brown and polar bears to be reciprocally monophyletic sister (or rather brother) lineages, without signals of introgression, 2) male-biased gene flow across continents and on phylogeographic time scales, and 3) male dispersal that links the Alaskan ABC islands population to mainland brown bears. Due to female philopatry, mtDNA provides a highly structured estimate of population differentiation, while male-biased gene flow is a homogenizing force for nuclear genetic variation. Our findings highlight the importance of analyzing both maternally and paternally inherited loci for a comprehensive view of phylogeographic history, and that mtDNA-based phylogeographic studies of many mammals should be reevaluated. Recent advances in sequencing technology render the analysis of Y-chromosomal variation feasible, even in nonmodel organisms.

Evidence of rapid change in genetic structure and diversity during range expansion in a recovering large terrestrial carnivore.

Recovery of natural populations occurs often with simultaneous or subsequent range expansions. According to population genetic theory, genetic structuring emerges at the expansion front together with decreasing genetic diversity, owing to multiple founder events. Thereupon, as the expansion proceeds and connectivity among populations is established, homogenization and a resurgence of genetic diversity are to be expected. Few studies have used a fine temporal scale combined with genetic sampling to track range expansions as they proceed in wild animal populations. As a natural experiment, the historical eradication of large terrestrial carnivores followed by their recovery and recolonization may facilitate empirical tests of these ideas. Here, using brown bear (Ursus arctos) as model species, we tested predictions from genetic theory of range expansion. Individuals from all over Finland were genotyped for every year between 1996 and 2010 using 12 validated autosomal microsatellite markers. A latitudinal shift of about 110 km was observed in the distribution and delineation of genetic clusters during this period. As the range expansion proceeded, we found, as theory predicts, that the degree of genetic structure decreased, and that both genetic variation and admixture increased. The genetic consequences of range expansions may first be detected after multiple generations, but we found major changes in genetic composition after just 1.5 generations, accompanied by population growth and increased migration. These rapid genetic changes suggest an ongoing concerted action of geographical and demographic expansion combined with substantial immigration of bears from Russia during the recovery of brown bears within the large ecosystem of northern Europe.

Y chromosome haplotype distribution of brown bears (Ursus arctos) in Northern Europe provides insight into population history and recovery.

High-resolution, male-inherited Y-chromosomal markers are a useful tool for population genetic analyses of wildlife species, but to date have only been applied in this context to relatively few species besides humans. Using nine Y-chromosomal STRs and three Y-chromosomal single nucleotide polymorphism markers (Y-SNPs), we studied whether male gene flow was important for the recent recovery of the brown bear (Ursus arctos) in Northern Europe, where the species declined dramatically in numbers and geographical distribution during the last centuries but is expanding now. We found 36 haplotypes in 443 male extant brown bears from Sweden, Norway, Finland and northwestern Russia. In 14 individuals from southern Norway from 1780 to 1920, we found two Y chromosome haplotypes present in the extant population as well as four Y chromosome haplotypes not present among the modern samples. Our results suggested major differences in genetic connectivity, diversity and structure between the eastern and the western populations in Northern Europe. In the west, our results indicated that the recovered population originated from only four male lineages, displaying pronounced spatial structuring suggestive of large-scale population size increase under limited male gene flow within the western subpopulation. In the east, we found a contrasting pattern, with high haplotype diversity and admixture. This first population genetic analysis of male brown bears shows conclusively that male gene flow was not the main force of population recovery.

Identification and Evaluation of 21 Novel Microsatellite Markers from the Autumnal Moth (Epirrita autumnata) (Lepidoptera: Geometridae).

The autumnal moth (Epirrita autumnata) is a cyclically outbreaking forest Lepidoptera with circumpolar distribution and substantial impact on Northern ecosystems. We have isolated 21 microsatellites from the species to facilitate population genetic studies of population cycles, outbreaks, and crashes. First, PCR primers and PCR conditions were developed to amplify 19 trinucleotide loci and two tetranucleotide loci in six multiplex PCR approaches and then analyzed for species specificity, sensitivity and precision. Twelve of the loci showed simple tandem repeat array structures while nine loci showed imperfect repeat structures, and repeat numbers varied in our material between six and 15. The application in population genetics for all the 21 microsatellites were further validated in 48 autumnal moths sampled from Northern Norway, and allelic variation was detected in 19 loci. The detected numbers of alleles per locus ranged from two to 13, and the observed and expected heterozygosities varied from 0.04 to 0.69 and 0.04 to 0.79, respectively. Evidence for linkage disequilibrium was found for six loci as well as indication of one null allele. We find that these novel microsatellites and their multiplex-PCR assays are suitable for further research on fine- and large-scale population-genetic studies of Epirrita autumnata.

Limited gene flow among brown bear populations in far Northern Europe? Genetic analysis of the east-west border population in the Pasvik Valley.

Noninvasively collected genetic data can be used to analyse large-scale connectivity patterns among populations of large predators without disturbing them, which may contribute to unravel the species' roles in natural ecosystems and their requirements for long-term survival. The demographic history of brown bears (Ursus arctos) in Northern Europe indicates several extinction and recolonization events, but little is known about present gene flow between populations of the east and west. We used 12 validated microsatellite markers to analyse 1580 hair and faecal samples collected during six consecutive years (2005-2010) in the Pasvik Valley at 70°N on the border of Norway, Finland and Russia. Our results showed an overall high correlation between the annual estimates of population size (N(c) ), density (D), effective size (N(e) ) and N(e) /N(c) ratio. Furthermore, we observed a genetic heterogeneity of ∼0.8 and high N(e) /N(c) ratios of ∼0.6, which suggests gene flow from the east. Thus, we expanded the population genetic study to include Karelia (Russia, Finland), Västerbotten (Sweden) and Troms (Norway) (477 individuals in total) and detected four distinct genetic clusters with low migration rates among the regions. More specifically, we found that differentiation was relatively low from the Pasvik Valley towards the south and east, whereas, in contrast, moderately high pairwise F(ST) values (0.91-0.12) were detected between the east and the west. Our results indicate ongoing limits to gene flow towards the west, and the existence of barriers to migration between eastern and western brown bear populations in Northern Europe.

Successful Production and Ligninolytic Activity of a Bacterial Laccase, Lac51, Made in Nicotiana benthamiana via Transient Expression.

Giant panda could have bamboo as their exclusive diet for about 2 million years because of the contribution of numerous enzymes produced by their gut bacteria, for instance laccases. Laccases are blue multi-copper oxidases that catalyze the oxidation of a broad spectrum of phenolic and aromatic compounds with water as the only byproduct. As a "green enzyme," laccases have potential in industrial applications, for example, when dealing with degradation of recalcitrant biopolymers, such as lignin. In the current study, a bacterial laccase, Lac51, originating from Pseudomonas putida and identified in the gut microbiome of the giant panda's gut was transiently expressed in the non-food plant Nicotiana benthamiana and characterized. Our results show that recombinant Lac51 exhibits bacterial laccase properties, with optimal pH and temperature at 7-8 and 40°C, respectively, when using syringaldazine as substrate. Moreover, we demonstrate the functional capability of the plant expressed Lac51 to oxidize lignin using selected lignin monomers that serve as substrates of Lac51. In summary, our study demonstrates the potential of green and non-food plants as a viable enzyme production platform for bacterial laccases. This result enriches our understanding of plant-made enzymes, as, to our knowledge, Lac51 is the first functional recombinant laccase produced in plants.

Genetic analysis indicates spatial-dependent patterns of sex-biased dispersal in Eurasian lynx in Finland.

Conservation and management of large carnivores requires knowledge of female and male dispersal. Such information is crucial to evaluate the population's status and thus management actions. This knowledge is challenging to obtain, often incomplete and contradictory at times. The size of the target population and the methods applied can bias the results. Also, population history and biological or environmental influences can affect dispersal on different scales within a study area. We have genotyped Eurasian lynx (180 males and 102 females, collected 2003-2017) continuously distributed in southern Finland (~23,000 km2) using 21 short tandem repeats (STR) loci and compared statistical genetic tests to infer local and sex-specific dispersal patterns within and across genetic clusters as well as geographic regions. We tested for sex-specific substructure with individual-based Bayesian assignment tests and spatial autocorrelation analyses. Differences between the sexes in genetic differentiation, relatedness, inbreeding, and diversity were analysed using population-based AMOVA, F-statistics, and assignment indices. Our results showed two different genetic clusters that were spatially structured for females but admixed for males. Similarly, spatial autocorrelation and relatedness was significantly higher in females than males. However, we found weaker sex-specific patterns for the Eurasian lynx when the data were separated in three geographical regions than when divided in the two genetic clusters. Overall, our results suggest male-biased dispersal and female philopatry for the Eurasian lynx in Southern Finland. The female genetic structuring increased from west to east within our study area. In addition, detection of male-biased dispersal was dependent on analytical methods utilized, on whether subtle underlying genetic structuring was considered or not, and the choice of population delineation. Conclusively, we suggest using multiple genetic approaches to study sex-biased dispersal in a continuously distributed species in which population delineation is difficult.

Harvest is associated with the disruption of social and fine-scale genetic structure among matrilines of a solitary large carnivore.

Harvest can disrupt wildlife populations by removing adults with naturally high survival. This can reshape sociospatial structure, genetic composition, fitness, and potentially affect evolution. Genetic tools can detect changes in local, fine-scale genetic structure (FGS) and assess the interplay between harvest-caused social and FGS in populations. We used data on 1614 brown bears, Ursus arctos, genotyped with 16 microsatellites, to investigate whether harvest intensity (mean low: 0.13 from 1990 to 2005, mean high: 0.28 from 2006 to 2011) caused changes in FGS among matrilines (8 matrilines; 109 females ≥4 years of age), sex-specific survival and putative dispersal distances, female spatial genetic autocorrelation, matriline persistence, and male mating patterns. Increased harvest decreased FGS of matrilines. Female dispersal distances decreased, and male reproductive success was redistributed more evenly. Adult males had lower survival during high harvest, suggesting that higher male turnover caused this redistribution and helped explain decreased structure among matrilines, despite shorter female dispersal distances. Adult female survival and survival probability of both mother and daughter were lower during high harvest, indicating that matriline persistence was also lower. Our findings indicate a crucial role of regulated harvest in shaping populations, decreasing differences among "groups," even for solitary-living species, and potentially altering the evolutionary trajectory of wild populations.

Activation of Notch signaling in cardiomyocytes during post-infarction remodeling.

OBJECTIVE: Notch signaling is crucial for cell-to-cell interaction during cardiovascular development and may influence differentiation, proliferation, and apoptotic events. We investigated whether Notch signaling is activated during myocardial remodeling in heart failure (HF). DESIGN: Myocardial gene expression and localization of Notch receptors (Notch1-4) and ligands (Jagged1-2, and Delta-like (Dll)-1 and 4) were investigated in rats with HF after induction of myocardial infarction and in humans with HF. RESULTS: All Notch receptors and ligands investigated and Notch intracellular domain (NICD) were present in rat and human myocardial tissue and in cardiomyocytes with differences in their relative expression levels and altered expression levels in failing vs. non-failing myocardium. In isolated rat cardiomyocytes, Notch3 and Notch4 appeared to be the major Notch receptors, and Notch3 and Notch4 mRNA levels and NICD-3 and -4 in cardiomyocytes were upregulated in chronic HF (p < 0.05), indicating increased Notch3 and Notch4 signaling. CONCLUSION: The Notch signaling system is present in the cardiomyocytes and activated in HF, indicating a role of Notch signaling during myocardial remodeling in HF.

Seasonal dynamics of lotic bacterial communities assessed by 16S rRNA gene amplicon deep sequencing.

Aquatic microbial diversity, composition, and dynamics play vital roles in sustaining water ecosystem functionality. Yet, there is still limited knowledge on bacterial seasonal dynamics in lotic environments. This study explores a temporal pattern of bacterial community structures in lotic freshwater over a 2-year period. The aquatic bacterial communities were assessed using Illumina MiSeq sequencing of 16S rRNA genes. Overall, the communities were dominated by α-, ß-, and γ-Proteobacteria, Bacteroidetes, Flavobacteriia, and Sphingobacteriia. The bacterial compositions varied substantially in response to seasonal changes (cold vs. warm), but they were rather stable within the same season. Furthermore, higher diversity was observed in cold seasons compared to warm periods. The combined seasonal-environmental impact of different physico-chemical parameters was assessed statistically, and temperature, suspended solids, and nitrogen were determined to be the primary abiotic factors shaping the temporal bacterial assemblages. This study enriches particular knowledge on the seasonal succession of the lotic freshwater bacteria.

Large-scale genetic admixture suggests high dispersal in an insect pest, the apple fruit moth.

Knowledge about population genetic structure and dispersal capabilities is important for the development of targeted management strategies for agricultural pest species. The apple fruit moth, Argyresthia conjugella (Lepidoptera, Yponomeutidae), is a pre-dispersal seed predator. Larvae feed on rowanberries (Sorbus aucuparia), and when rowanberry seed production is low (i.e., inter-masting), the moth switches from laying eggs in rowanberries to apples (Malus domestica), resulting in devastating losses in apple crops. Using genetic methods, we investigated if this small moth expresses any local genetic structure, or alternatively if gene flow may be high within the Scandinavian Peninsula (~850.000 km2, 55o - 69o N). Genetic diversity was found to be high (n = 669, mean He = 0.71). For three out of ten tetranucleotide STRs, we detected heterozygote deficiency caused by null alleles, but tests showed little impact on the overall results. Genetic differentiation between the 28 sampling locations was very low (average FST = 0.016, P < 0.000). Surprisingly, we found that all individuals could be assigned to one of two non-geographic genetic clusters, and that a third, geographic cluster was found to be associated with 30% of the sampling locations, with weak but significant signals of isolation-by-distance. Conclusively, our findings suggest wind-aided dispersal and spatial synchrony of both sexes of the apple fruit moth over large areas and across very different climatic zones. We speculate that the species may recently have had two separate genetic origins caused by a genetic bottleneck after inter-masting, followed by rapid dispersal and homogenization of the gene pool across the landscape. We suggest further investigations of spatial genetic similarities and differences of the apple fruit moth at larger geographical scales, through life-stages, across inter-masting, and during attacks by the parasitoid wasp (Microgaster politus).

Genome- and transcriptome-derived microsatellite loci in lumpfish Cyclopterus lumpus: molecular tools for aquaculture, conservation and fisheries management.

The lumpfish Cyclopterus lumpus is commercially exploited in numerous areas of its range in the North Atlantic Ocean, and is important in salmonid aquaculture as a biological agent for controlling sea lice. Despite the economic importance, few genetic resources for downstream applications, such as linkage mapping, parentage analysis, marker-assisted selection (MAS), quantitative trait loci (QTL) analysis, and assessing adaptive genetic diversity are currently available for the species. Here, we identify both genome- and transcriptome-derived microsatellites loci from C. lumpus to facilitate such applications. Across 2,346 genomic contigs, we detected a total of 3,067 microsatellite loci, of which 723 were the most suitable ones for primer design. From 116,555 transcriptomic unigenes, we identified a total of 231,556 microsatellite loci, which may indicate a high coverage of the available STRs. Out of these, primer pairs could only be designed for 6,203 loci. Dinucleotide repeats accounted for 89 percent and 52 percent of the genome- and transcriptome-derived microsatellites, respectively. The genetic composition of the dominant repeat motif types showed differences from other investigated fish species. In the genome-derived microsatellites AC/GT (67.8 percent), followed by AG/CT (15.1 percent) and AT/AT (5.6 percent) were the major motifs. Transcriptome-derived microsatellites showed also most dominantly the AC/GT repeat motif (33 percent), followed by A/T (26.6 percent) and AG/CT (11 percent). Functional annotation of microsatellite-containing transcriptomic sequences showed that the majority of the expressed sequence tags encode proteins involved in cellular and metabolic processes, binding activity and catalytic reactions. Importantly, STRs linked to genes involved in immune system process, growth, locomotion and reproduction were discovered in the present study. The extensive genomic marker information reported here will facilitate molecular ecology studies, conservation initiatives and will benefit many aspects of the breeding programmes of C. lumpus.

Faecal pollution affects abundance and diversity of aquatic microbial community in anthropo-zoogenically influenced lotic ecosystems.

The aquatic microbiota is known to be an important factor in the sustainability of the natural water ecosystems. However, the microbial community also might include pathogens, which result in very serious waterborne diseases in humans and animals. Faecal pollution is the major cause of these diseases. Therefore, it is of immense importance to assess the potential impact of faecal pollution, originating from both anthropogenic and zoogenic sources, on the profile of microbial communities in natural water environments. To this end, the microbial taxonomic diversity of lotic ecosystems in different regions of Norway, representing urban and rural areas, exposed to various levels of faecal pollution, was investigated over the course of a 1-year period. The highest microbial diversity was found in rural water that was the least faecally polluted, while the lowest was found in urban water with the highest faecal contamination. The overall diversity of the aquatic microbial community was significantly reduced in severely polluted water. In addition, the community compositions diverged between waters where the dominant pollution sources were of anthropogenic or zoogenic origin. The results provide new insight into the understanding of how faecal water contamination, specifically that of different origins, influences the microbial diversity of natural waters.

Aquatic microbial diversity associated with faecal pollution of Norwegian waterbodies characterized by 16S rRNA gene amplicon deep sequencing.

Faecal contamination is one of the major factors affecting biological water quality. In this study, we investigated microbial taxonomic diversity of faecally polluted lotic ecosystems in Norway. These ecosystems comprise tributaries of drinking water reservoirs with moderate and high faecal contamination levels, an urban creek exposed to extremely high faecal pollution and a rural creek that was the least faecally polluted. The faecal water contamination had both anthropogenic and zoogenic origins identified through quantitative microbial source tracking applying host-specific Bacteroidales 16S rRNA genetic markers. The microbial community composition revealed that Proteobacteria and Bacteroidetes (70-90% relative abundance) were the most dominant bacterial phyla, followed by Firmicutes, especially in waters exposed to anthropogenic faecal contamination. The core archaeal community consisted of Parvarchaeota (mainly in the tributaries of drinking water reservoirs) and Crenarchaeota (in the rural creek). The aquatic microbial diversity was substantially reduced in water with severe faecal contamination. In addition, the community compositions diverge between waters with dominant anthropogenic or zoogenic pollution origins. These findings present novel interpretations of the effect of anthropo-zoogenic faecal water contamination on microbial diversity in lotic ecosystems.