Ancient DNA reveals the chronology of walrus ivory trade from Norse Greenland.

The importance of the Atlantic walrus ivory trade for the colonization, peak, and collapse of the medieval Norse colonies on Greenland has been extensively debated. Nevertheless, no studies have directly traced medieval European ivory back to distinct Arctic populations of walrus. Analysing the entire mitogenomes of 37 archaeological specimens from Europe, Svalbard, and Greenland, we here discover that Atlantic walrus comprises two monophyletic mitochondrial (MT) clades, which diverged between 23 400 and 251 120 years ago. Our improved genomic resolution allows us to reinterpret the geographical distribution of partial MT data from 306 modern and nineteenth-century specimens, finding that one of these clades was exclusively accessible to Greenlanders. With this discovery, we ascertain the biological origin of 23 archaeological specimens from Europe (most dated between 900 and 1400 CE). These results reveal a significant shift in trade from an early, predominantly eastern source towards a near exclusive representation of Greenland ivory. Our study provides empirical evidence for how this remote Arctic resource was progressively integrated into a medieval pan-European trade network, contributing to both the resilience and vulnerability of Norse Greenland society.This work was supported by the Nansenfondet, the Research Council of Norway projects 262777 and 230821, and the Leverhulme Trust project ‘Northern Journeys’ MRF-2013-065

First and third trimester serum concentrations of adropin and copeptin in gestational diabetes mellitus and normal pregnancy

Objectives: Gestational diabetes mellitus (GDM) is a metabolic disease diagnosed in 1.7% up to 11.6% pregnancies. The prevalence of adverse pregnancy outcome is significantly higher in the case of early onset of diabetes mellitus. Adropin is a hormone promoting carbohydrate oxidation over fat oxidation, and influence nitric oxide synthase. Copeptin is a cleavage product of the vasopressin precursor recently correlated with diabetes mellitus. The aim of the study was to determine maternal serum adropin and copeptin concentrations in women with early and late manifestation of GDM and to discuss their potential role as biochemical markers of insulin resistance. Material and methods: Case-control study on 58 pregnant Caucasian women. Serum levels of adropin and copeptin were assessed in patients with early onset (GDM1) and classical gestational diabetes mellitus (GDM2). Complications such as macrosomia and hypotrophy were evaluated. Results: There was no significant difference between the study and the control group (age, BMI, parity). Fetal growth disturbance rate was 37.5% in GDM1, 11% in GDM2 and 6% in controls. Adropin concentration in GDM patients was significantly higher than in control group (p < 0.001), but there was no difference between GDM1 and GDM2 group. High serum concentration of adropin positively correlated with elevated HbA1c (p < 0.05). The groups did not differ in terms of copeptin serum concentration. Conclusions: High adropin serum concentration in GDM patients is associated with increased risk of fetal growth disturbances, possibly due to improper placentation. According to our prospective study, neither copeptin nor adropin serum concentration are useful to discriminate between early and late onset of gestational diabetes mellitus

Microbial danger signals control transcriptional induction of distinct MHC class I L lineage genes in Atlantic salmon

Source at https://doi.org/10.3389/fimmu.2019.02425. Antigen processing and presentation by major histocompatibility complex (MHC) molecules is a cornerstone in vertebrate immunity. Like mammals, teleosts possess both classical MHC class I and multiple families of divergent MHC class I genes. However, while certain mammalian MHC class I-like molecules have proven to be integral in immune regulation against a broad array of pathogens, the biological relevance of the different MHC class I lineages in fish remains elusive. This work focuses on MHC class I L lineage genes and reveals unique regulatory patterns of six genes (Sasa-lia, Sasa-lda, Sasa-lca, Sasa-lga, Sasa-lha, and Sasa-lfa) in antimicrobial immunity of Atlantic salmon (Salmo salar L.). Using two separate in vivo challenge models with different kinetics and immune pathologies combined with in vitro stimulation using viral and bacterial TLR ligands, we show that de novo synthesis of different L lineage genes is distinctly regulated in response to various microbial stimuli. Prior to the onset of classical MHC class I gene expression, lia was rapidly and systemically induced in vivo by the single-stranded (ss) RNA virus salmonid alpha virus 3 (SAV3) but not in response to the intracellular bacterium Piscirickettsia salmonis. In contrast, lga expression was upregulated in response to both viral and bacterial stimuli. A role for distinct MHC class I L-lineage genes in anti-microbial immunity in salmon was further substantiated by a marked upregulation of lia and lga gene expression in response to type I IFNa stimulation in vitro. Comparably, lha showed no transcriptional induction in response to IFNa stimulation but was strongly induced in response to a variety of viral and bacterial TLR ligands. In sharp contrast, lda showed no response to viral or bacterial challenge. Similarly, induction of lca, which is predominantly expressed in primary and secondary lymphoid tissues, was marginal with the exception of a strong and transient upregulation in pancreas following SAV3 challenge Together, these findings suggest that certain Atlantic salmon MHC class I L lineage genes play important and divergent roles in early anti-microbial response and that their regulation, in response to different activation signals, represents a system for selectively promoting the expression of distinct non-classical MHC class I genes in response to different types of immune challenges

Combining bleach and mild predigestion improves ancient DNA recovery from bones.

The feasibility of genome-scale studies from archaeological material remains critically dependent on the ability to access endogenous, authentic DNA. In the majority of cases, this represents a few per cent of the DNA extract, at most. A number of specific pre-extraction protocols for bone powder aimed to improve ancient DNA recovery before library amplification have recently been developed. Here, we test the effects of combining two of such protocols, a bleach wash and a predigestion step, on 12 bone samples of Atlantic cod and domestic horse aged 750-1350 cal. years before present. Using high-throughput sequencing, we show that combined together, bleach wash and predigestion consistently yield DNA libraries with higher endogenous content than either of these methods alone. Additionally, the molecular complexity of these libraries is improved and endogenous DNA templates show larger size distributions. Other library characteristics, such as DNA damage profiles or the composition of microbial communities, are little affected by the pre-extraction protocols. Application of the combined protocol presented in this study will facilitate the genetic analysis of an increasing number of ancient remains and will reduce the cost of whole-genome sequencing

Ancient DNA reveals the Arctic origin of Viking Age cod from Haithabu, Germany.

Knowledge of the range and chronology of historic trade and long-distance transport of natural resources is essential for determining the impacts of past human activities on marine environments. However, the specific biological sources of imported fauna are often difficult to identify, in particular if species have a wide spatial distribution and lack clear osteological or isotopic differentiation between populations. Here, we report that ancient fish-bone remains, despite being porous, brittle, and light, provide an excellent source of endogenous DNA (15-46%) of sufficient quality for whole-genome reconstruction. By comparing ancient sequence data to that of modern specimens, we determine the biological origin of 15 Viking Age (800-1066 CE) and subsequent medieval (1066-1280 CE) Atlantic cod (Gadus morhua) specimens from excavation sites in Germany, Norway, and the United Kingdom. Archaeological context indicates that one of these sites was a fishing settlement for the procurement of local catches, whereas the other localities were centers of trade. Fish from the trade sites show a mixed ancestry and are statistically differentiated from local fish populations. Moreover, Viking Age samples from Haithabu, Germany, are traced back to the North East Arctic Atlantic cod population that has supported the Lofoten fisheries of Norway for centuries. Our results resolve a long-standing controversial hypothesis and indicate that the marine resources of the North Atlantic Ocean were used to sustain an international demand for protein as far back as the Viking Age.Leverhulme Trust (MRF-2013-065

Genomic stability through time despite decades of exploitation in cod on both sides of the Atlantic

The mode and extent of rapid evolution and genomic change in response to human harvesting are key conservation issues. Although experiments and models have shown a high potential for both genetic and phenotypic change in response to fishing, empirical examples of genetic responses in wild populations are rare. Here, we compare whole-genome sequence data of Atlantic cod (Gadus morhua) that were collected before (early 20th century) and after (early 21st century) periods of intensive exploitation and rapid decline in the age of maturation from two geographically distinct populations in Newfoundland, Canada, and the northeast Arctic, Norway. Our temporal, genome-wide analyses of 346,290 loci show no substantial loss of genetic diversity and high effective population sizes. Moreover, we do not find distinct signals of strong selective sweeps anywhere in the genome, although we cannot rule out the possibility of highly polygenic evolution. Our observations suggest that phenotypic change in these populations is not constrained by irreversible loss of genomic variation and thus imply that former traits could be reestablished with demographic recovery.publishedVersio

The preservation of ancient DNA in archaeological fish bone

The field of ancient DNA is dominated by studies focusing on terrestrial vertebrates. This taxonomic bias limits our understanding of endogenous DNA preservation for species with different bone physiology, such as teleost fish. Teleost bone is typically brittle, porous, lightweight, and is characterized by a lack of bone remodeling during growth. All of these factors potentially affect DNA preservation. Using high-throughput shotgun sequencing, we here investigate the preservation of DNA in a range of different bone elements from over 200 archaeological Atlantic cod (Gadus morhua) specimens from 38 sites in northern Europe, dating up to 8000 years before present. We observe that the majority of archaeological sites (79%) yield endogenous DNA, with 40% of sites providing samples containing high levels (>20%). Library preparation success and levels of endogenous DNA depend mainly on excavation site and pre-extraction laboratory treatment. The use of pre-extraction treatments lowers the rate of libraries that can be sequenced, although — if successful — the fraction of endogenous DNA can be improved by several orders of magnitude. This trade-off between library preparation success and levels of endogenous DNA allows for alternative extraction strategies depending on the requirements of down-stream analyses and research questions. Finally, we do not find particular bone elements to yield higher levels of endogenous DNA, as is the case for denser bones in mammals. Our results highlight the potential of archaeological fish bone as a source for ancient DNA and suggest a possible role of bone remodeling in the preservation of endogenous DNA

Bioelectrodes based on human-friendly lactic acid bacteria - the influence of temperature on their electrochemical activity

Mikrobiologiczne ogniwa paliwowe (z ang. Microbial Fuel Cells, MFC) to bardzo obiecująca technologia pozyskiwania energii odnawialnej. Należą one do układów bioelektrochemicznych (z ang. Bioelectrochemical systems, BESs), które wykorzystują bakterie bądź grzyby do generowania prądu. Niezbędne w tych układach mikroorganizmy wykorzystują swoje procesy metaboliczne do wytwarzania energii. Przetwarzają one związki organiczne, m.in. glukozę, bezpośrednio w elektryczność. Obecnie stosowane układy bazują na elektrodach węglowych i, najczęściej, bakteriach zjadliwych, przez co takie bioelektrody nie są uniwersalne. Dlatego też wciąż poszukuje się nowych rozwiązań mogących znaleźć zastosowanie w układach bioelektrochemicznych.W związku z tym zaproponowano wykorzystanie nowych bioelektrod na bazie dobrze przewodzącej miedzi pokrytej złotem oraz użycie bakterii kwasu mlekowego Lactobacillus rhamnosus GG, które są w pełni przyjazne zarówno dla środowiska, jak również dla człowieka. Koncepcją pracy było zbadanie wpływu temperatury pomiaru oraz czasu hodowli bakterii na powierzchniach elektrod na odpowiedź prądową. W celu zobrazowania elektrod na poszczególnych etapach przygotowania posłużono się skaningowym mikroskopem elektronowym (SEM), a ich charakterystyka elektrochemiczna odbywała się na podstawie pomiarów OCP i CV w zadanych warunkach pomiarowych. Uzyskane w pracy wyniki przyczynią się do dokładniejszego poznania procesów zachodzących w badanych układach.Microbial Fuel Cells (MFC) is a very promising technology for acquiring renewable energy. They belong to Bioelectrochemical Systems (BESs) that use bacteria or fungi to generate electricity. The necessary microorganisms in these systems use their metabolic processes to generate energy. They process organic compounds, including glucose, directly into electricity. Current systems are based on carbon electrodes and, most frequently, virulent bacteria, so that these bioelectrodes are not universal. Therefore, new solutions that may be used in bioelectrochemical systems are still being sought for.Therefore, the use of new bioelectrodes based on well-conducting copper coated with gold and the use of lactic acid bacteria Lactobacillus rhamnosus GG, which are fully environmentally and human friendly, are proposed. The concept of the work was to investigate the influence of the measurement temperature and the time of bacterial cultivation on the surfaces of the electrodes for the current response. In order to visualize the electrodes, the scanning electron microscope (SEM) was used at particular stages of the preparation, and their electrochemical characteristics were based on OCP and CV measurements at the given measurement conditions. The results obtained in the work will contribute to a more accurate understanding of the processes occurring in the studied systems

A stainless-steel mortar, pestle and sleeve design for the efficient fragmentation of ancient bone

Different types of milling equipment – such as oscillating ball mills, freezer mills, mortar and pestle – can be used to fragment ancient bone prior to DNA extraction. However, each of these tools is associated with practical drawbacks. Here, we present the design for a stainless-steel mortar and pestle, with a removable sleeve to contain bone material. The tool is easy to clean, practical and its simplicity allows university workshops equipped with a lathe, boring tools and a milling machine to make these components at local expense. This design allows for the efficient fragmentation of ancient bone and improves sample throughput. This design is recommended as a useful, economical addition to existing laboratory equipment for the handling of ancient bone