Diversity and distribution of cultured endolichenic fungi in the Ny-Ålesund Region,Svalbard (High Arctic)

Endolichenic fungi within 17 lichen species in the area near Ny-Ålesund (Svalbard, High Arctic) were studied by a culture-based method. The 247 fungal isolates were obtained from 2712 lichen thallus segments. The colonization rate of endolichenic fungi ranged from 1.6 to 26.5 %, respectively. These isolates were identified to 40 fungal taxa, including 35 Ascomycota (10 orders), 4 Basidiomycota (3 orders), and 1 unidentified fungus. Thelebolales was the most abundant order, while Sordariales were the most diverse order. The common fungal taxa shared by more than 3 lichen species were Thelebolus microsporus (93 isolates), Coniochaeta hoffmannii (7 isolates), Sarocladium kiliense (33 isolates), Coniochaeta sp. 1 (5 isolates), Coniochaeta sp. 4 (28 isolates), and Coniochaeta sp. 2 (5 isolates). Low Sorenson’s similarity coefficients were observed among different lichen species, indicating that host-related factor may shape the endolichenic fungal communities in this region. In addition, no endolichenic fungal taxa were previously found in the Antarctica and Austrian Alps, suggesting endolichenic fungal communities in this region might be also shaped by the Arctic climate. The results demonstrate the existence of specific cultured endolichenic fungal species, which may be suitable objects for further study of their possible functional roles in the lichen thalli.     

Ecosystem development and carbon cycle on a glacier foreland in the high Arctic, Ny-Ålesund, Svalbard

The Arctic terrestrial ecosystem is thought to be extremely susceptible to climate change. However, because of the diverse responses of ecosystem components to change, an overall response of the ecosystem carbon cycle to climate change is still hard to predict. In this review, we focus on several recent studies conducted to clarify the pattern of the carbon cycle on the deglaciated area of Ny-Ålesund, Svalbard in the high Arctic. Vegetation cover and soil carbon pools tended to increase with the progress of succession. However, even in the latter stages of succession, the size of the soil carbon pool was much smaller than those reported for the low Arctic tundra. Cryptogams contributed the major proportion of phytomass in the later stages. However, because of water limitation, their net primary production was smaller than that of the vascular plants. The compartment model that incorporated major carbon pools and flows suggested that the ecosystem of the later stages is likely to be a net sink of carbon at least for the summer season. Based on the eco-physiological characteristics of the major ecosystem components, we suggest several possible scenarios of future changes in the ecosystem carbon cycle.     

Changes in viral and bacterial communities during the ice-melting season in the coastal Arctic (Kongsfjorden, Ny-Ålesund)

Microbial communities in Arctic coastal waters experience dramatic changes in environmental conditions during the spring to summer transition period, potentially leading to major variations in the relationship between viral and prokaryotic communities. To document these variations, a number of physico-chemical and biological parameters were determined during the ice-melting season in the coastal Arctic (Kongsfjorden, Ny-?lesund, Spitsbergen). The bacterial and viral abundance increased during the spring to summer transition period, probably associated to the increase in temperature and the development of a phytoplankton bloom. The increase in viral abundance was less pronounced than the increase in prokaryotic abundance; consequently, the viral to prokaryotic abundance ratio decreased. The bacterial and viral communities were stratified as determined by Automated Ribosomal Intergenic Spacer Analysis and Randomly Amplified Polymorphic DNA-PCR respectively. Both the bacterial and viral communities were characterized by a relatively low number of operational taxonomic units (OTUs). Despite the apparent low complexity of the bacterial and viral communities, the link between these two communities was weak over the melting season, as suggested by the different trends of prokaryotic and viral abundance during the sampling period. This weak relationship between the two communities might be explained by UV radiation and suspended particles differently affecting the viruses and prokaryotes in the coastal Arctic during this period. Based on our results, we conclude that the viral and bacterial communities in the Arctic were strongly affected by the variability of the environmental conditions during the transition period between spring and summer.     

Bacterial Diversity and Bioprospecting for Cold-Active Lipases,Amylases and Proteases,from Culturable Bacteria of Kongsfjorden and Ny-Ålesund,Svalbard, Arctic

Culturable bacterial diversity of seven marine sediment samples of Kongsfjorden and a sediment and a soil sample from Ny-Ålesund, Svalbard, Arctic was studied. The bacterial abundance in the marine sediments of Kongsfjorden varied marginally (0.5 × 10³–1.3 × 10⁴ cfu/g sediment) and the bacterial number in the two samples collected from the shore of Ny-Ålesund also was very similar (0.6 × 10⁴ and 3.4 × 10⁴, respectively). From the nine samples a total of 103 bacterial isolates were obtained and these isolates could be grouped in to 47 phylotypes based on the 16S rRNA gene sequence belonging to 4 phyla namely Actinobacteria, Bacilli, Bacteroidetes and Proteobacteria. Representatives of the 47 phylotypes varied in their growth temperature range (4–37°C), in their tolerance to NaCl (0.3–2 M NaCl) and growth pH range (2–11). Representatives of 26 phylotypes exhibited amylase and lipase activity either at 5 or 20°C or at both the temperatures. A few of the representatives exhibited amylase and/or lipase activity only at 5°C. None of the phylotypes exhibited protease activity. Most of the phylotypes (38) were pigmented. Fatty acid profile studies indicated that short chain fatty acids, unsaturated fatty acids, branched fatty acids, the cyclic and the cis fatty acids are predominant in the psychrophilic bacteria.     

Seabirds colonized Ny-Ålesund, Svalbard, Arctic ~9,400 years ago

A 118-cm-long and well-preserved sediment profile in a paleo-notch, which was formed by ocean wave action before rising to the terrace, was collected from the first terrace of Ny-Ålesund, Svalbard, Arctic. The bottom of this profile was dated as 9,400 years B.P. based on two radiocarbon dates of fossil mollusc shell fragments. The organic material in the sediment was identified by δ¹³C_org–C/N plot and δ¹⁵N_org characteristics to be predominantly composed of seabird guano, which was transported from the ocean via preying and excreting by seabirds. These results indicate that seabirds have inhabited Ny-Ålesund since 9,400 years B.P. after Kongsfjorden was completely deglaciated. This is the first report on Holocene seabird occupation on Ny-Ålesund and it provides the foundation for understanding the ecological history of seabirds in Svalbard in Holocene.     

Host-specificity of moss-associated fungal communities in the Ny-Ålesund region (Svalbard,High Arctic) as revealed by amplicon pyrosequencing

Fungal communities play a significant role in regulating ecological processes in the Arctic tundra. However, the extent to which the Arctic moss species and host types (moss, lichen and vascular plant) determine the richness, diversity, and composition of fungal communities at a local scale has not been quantitatively explored. Using 454 pyrosequencing in the current study, we characterized the fungal communities associated with six moss species (Andreaea rupestris, Bryum pseudotriquetrum, Hymenoloma crispulum, Polytrichastrum alpinum, Racomitrium lanuginosum, and Sanionia uncinata) and compared them with fungal communities associated with lichens and vascular plants in the Ny-Ålesund region (High Arctic). Host-species preference had greater explanatory power than geographical factors (longitude, latitude, elevation) in shaping moss-associated fungal communities. Fungal communities associated with mosses differed significantly from those associated with vascular plants and lichens, suggesting specificity of the fungal communities among three host types. Pairwise comparison analysis also indicated that the relative abundance of many taxonomic groups (e.g., Chaetothyriales, Leotiales, Catenulifera, Alatospora, and Toxicocladosporium) significantly differed between mosses and the other two host types. These results suggest host factors significantly affect the distribution of the fungal species associated with these moss species in the local-scale Arctic tundra.     

Isolation of facultatively anaerobic soil bacteria from Ny-Ålesund, Svalbard

Anaerobic conditions in soil commonly occur even in upland environments. Physiological and biogeochemical properties of individual anaerobic bacteria, however, have been poorly understood due to difficulties in culture. This study aimed to isolate anaerobic bacteria in the Arctic tundra soil and to identify their physiological characteristics. Anaerobic culture and 16S rRNA gene sequence-based phylogenetic analysis showed that total 33 bacterial strains were affiliated with 15 species from the following 8 genera: Bacillus, Carnobacterium, Clostridium, Paenibacillus, and Trichococcus (Firmicutes), Pseudomonas and Rahnella (Gamma-proteobacteria), and Cellulomonas (Actinobacteria). All isolates were identified as facultatively anaerobic bacteria; this finding might be partially attributed to the characteristics of sampling sites, which temporarily developed anaerobic conditions because of the presence of stagnant melting snow. Six of the 33 bacterial strains were revived subsequently from glycerol stocks held ?80 °C, and these were used for the physiological study: four isolates from Firmicutes, one isolate from Gamma-proteobacteria, and one isolate from Actinobacteria. Five isolates except KOPRI 80146 (Bacillus sp.) could grow at either 4 or 10 °C within a week. All six isolates showed cellulase or protease activities at 10 or 15 °C. Endospores were observed from four isolates belonging to Firmicutes. These physiological characteristics may contribute to the survival of these organisms at low temperatures and to their involvement in biogeochemical cycles in the tundra soil. These isolates may be used for further detailed studies for identifying their cold adaptation mechanisms and ecological roles in the Arctic.     

Photosynthetic characteristics and biomass distribution of the dominant vascular plant species in a high Arctic tundra ecosystem,Ny-Ålesund,Svalbard: implications for their role in ecosystem carbon gain

Studies on terrestrial ecosystems in the high Arctic region have focused on the response of these ecosystems to global environmental change and their carbon sequestration capacity in relation to ecosystem function. We report here our study of the photosynthetic characteristics and biomass distribution of the dominant vascular plant species, Salix polaris, Dryas octopetala and Saxifraga oppositifolia, in the high Arctic tundra ecosystem at Ny-Alesund, Svalbard (78.5 degrees N, 11.5 degrees E). We also estimated net primary production (NPP) along both the successional gradient created by the proglacial chronosequence and the topographical gradient. The light-saturated photosynthesis rate (A (max)) differed among the species, with approximately 124.1 nmol CO(2) g(-1)leaf s(-1) for Sal. polaris, 57.8 for D. octopetala and 24.4 for Sax. oppositifolia, and was highly correlated with the leaf nitrogen (N) content for all three species. The photosynthetic N use efficiency was the highest in Sal. polaris and lowest in Sax. oppositifolia. Distributions of Sal. polaris and D. octopetala were restricted to the area where soil nutrient availability was high, while Sax. oppositifolia was able to establish at the front of a glacier, where nutrient availability is low, but tended to be dominated by other vascular plants in high nutrient areas. The NPP reflected the photosynthetic capacity and biomass distribution in that it increased with the successional status; the contribution of Sal. polaris reached as high as 12-fold that of Sax. oppositifolia.     

Potent toxins in Arctic environments – Presence of saxitoxins and an unusual microcystin variant in Arctic freshwater ecosystems

Cyanobacteria are the predominant phototrophs in freshwater ecosystems of the polar regions where they commonly form extensive benthic mats. Despite their major biological role in these ecosystems, little attention has been paid to their physiology and biochemistry. An important feature of cyanobacteria from the temperate and tropical regions is the production of a large variety of toxic secondary metabolites. In Antarctica, and more recently in the Arctic, the cyanobacterial toxins microcystin and nodularin (Antarctic only) have been detected in freshwater microbial mats. To date other cyanobacterial toxins have not been reported from these locations. Five Arctic cyanobacterial communities were screened for saxitoxin, another common cyanobacterial toxin, and microcystins using immunological, spectroscopic and molecular methods. Saxitoxin was detected for the first time in cyanobacteria from the Arctic. In addition, an unusual microcystin variant was identified using liquid chromatography–mass spectrometry. Gene expression analyses confirmed the analytical findings, whereby parts of the sxt and mcy operon involved in saxitoxin and microcystin synthesis, were detected and sequenced in one and five of the Arctic cyanobacterial samples, respectively. The detection of these compounds in the cryosphere improves the understanding of the biogeography and distribution of toxic cyanobacteria globally. The sequences of sxt and mcy genes provided from this habitat for the first time may help to clarify the evolutionary origin of toxin production in cyanobacteria.     

The biochemical diversity of life near and above 100°C in marine environments

Hyperthermophilic micro-organisms grow at temperatures above 90 °C with a current upper limit of 113 °C. They are a recent discovery in the microbial world and have been isolated mainly from marine geothermal environments, which include both shallow and deep sea hydrothermal vents. By 16S rRNA analyses they are the most slowly evolving of all extant life forms, and all but two of the nearly 20 known genera are classified as Archaea (formerly Archaebacteria). Almost all hyperthermophiles are strict anaerobes. They include species of methanogens, iron-oxidizers and sulphate reducers, but the majority are obligate heterotrophs that depend upon the reduction of elemental sulphur (S°) to hydrogen sulphide for significant growth. The heterotrophs utilize proteinaceous materials as carbon and energy sources, although a few species are also saccharolytic. A scheme for electron flow during the oxidation of carbohydrates and peptides and the reduction of S° has been proposed. Two S°-reducing enzymes have been purified from the cytoplasm of one hyperthermophile (T(opt) 100 °C) that is able to grow either with and without S°. However, the mechanisms by which S° reduction is coupled to energy conservation in this organism and in obligate S°-reducing hyperthermophiles is not known. In the heterotrophs, sugar fermentation is achieved by a novel glycolytic pathway involving unusual ADP-dependent kinases and ATP synthetases, and novel oxidoreductases that are ferredoxin- rather than NAD(P)-linked. Similarly, peptide fermentation involves several unusual ferredoxin-linked oxidoreductases not found in mesophilic organisms. Several of these oxido-reductases contain tungsten, an element that is rarely used in biological systems. Tungsten is present in exceedingly low concentrations in normal sea water, but hydrothermal systems contain much higher tungsten concentrations, more than sufficient to support hyperthermophilic life.     

Bacterial community in cold and alkaline environments of Hoh Xil basin in Qinghai–Tibet Plateau and isolation of potential sources of microbiota

The Hoh Xil basin is the largest Cenozoic sedimentary basin in the Qinghai–Tibet Plateau (QTP) with an average altitude of above 5000 m. It is also the coldest region in the QTP. However, due to the difficulty of sample collection caused by the harsh natural environment, a limited number of studies have been conducted on soil microorganisms in this region. We used culture-dependent and independent methods to investigate the bacterial communities in desert soil (n1), saline–alkali land (n2), saline–alkali wetland (n3), and soda lake sediment (n4). The results showed distinct bacterial communities between different environmental types. We found that the Chao1 and Shannon diversity indices of n1 were significantly lower than those of n4 (P < 0.05). At the phylum level, all samples were dominated by representatives of Proteobacteria, Bacteroidetes, and Actinobacteria, which were similar to the findings of previous studies on the desert soil in the same region. Moreover, we identified 10 strains of bacteria from 109 isolates, most of which belonged to Pseudomonas (90.8%). The growth of the isolate k9 was optimal at a high pH value (pH 10.0) and a low temperature (5 °C), and this stain could produce extracellular enzyme (alkaline phosphatase, acid phosphatase, and naphthol-AS-BI-phosphohydrolase) under alkaline (pH 10) and cold (5 °C) condition. These results demonstrate the diversity of bacteria in the Hoh Xil basin and identify potential psychrophilic and alkaliphilic bacteria with multiple types of extracellular enzyme activity.     

Characteristics of ammonia oxidation potentials and ammonia oxidizers in mineral soil under <Emphasis Type="Italic">Salix polaris</Emphasis>–moss vegetation in Ny-Ålesund,Svalbard

Although nitrification is a unique and important process in the nitrogen cycle with respect to ammonium consumption and nitrate production, limited information on this process is available for high-Arctic soils. We elucidated the ammonia oxidation potentials (AOPs) and characteristics of ammonia-oxidizing bacteria (AOB) and archaea (AOA) in mineral soils under climax vegetation, i.e., Salix polaris (polar willow)–moss vegetation, on a coastal hill in Ny-Ålesund, Svalbard. AOPs at 10 °C were determined by incubation with sufficient substrate (2 mM ammonium). The ammonia monooxygenase subunit A (amoA) genes of AOB and AOA were analyzed by using quantitative polymerase chain reaction and pyrosequencing. AOPs ranged from 1.1 to 14.1 ng N g^?1 dry soil h^?1—relatively low but of a similar order to the gross nitrification rates reported in another Svalbard study. AOP was positively correlated with thickness of the moss layer (P < 0.01), soil water content, and ammonium nitrogen content (P < 0.05). The population sizes of both AOB and AOA were not significantly related to AOP or edaphic factors. For AOB-amoA, six major operational taxonomic units (OTUs) were identified, all of which were classified into the Nitrosospira Mount Everest cluster. For AOA-amoA, six major OTUs were also identified, five of which were grouped with sequences from cold environments within clade A of the Nitrososphaera cluster, i.e., species known to have low, or no, AOP. It is, therefore, possible that the AOPs measured at the study site were driven mainly by psychrotolerant AOB.     

Production,clearance rates and metabolic fate of estradiol-17β in the plasma of the laying hen

A single dose of tritiated estradiol-17β (³H-E₂β) was injected i.v. into 5 high egg producing White Leghorn hens, 31 weeks of age, at 19.2 ± 2.1 (mean ± S.D.) hr before oviposition. Blood (2 ml) was sampled at approximately 5 min intervals over 40 min. Whenever possible, metabolites were monitored and identified by the double isotope technique with the addition of the corresponding ¹⁴C-labelled standards to plasma prior to analysis. The metabolic half-life and clearance rate of ³H-E₂β in plasma were 10.9 ± 1.9 min and 118 ± 18 ml/min/kg body weight, respectively. The calculated production rate of E₂β at 19.2 hr before oviposition was 19.5 ± 5.7 ng/min based on the plasma level (93±22 pg/ml) measured at that time. The relative concentrations (% of plasma radioactivity) of the major metabolites isolated at 5.7 ± 0.6 min post injection were, in descending order: estradiol-17β-3-sulfate (E₂β-3S : 14.9 ± 2.7), estradiol-17α-3-sulfate (E₂α-3S; 5.7 ± 0.3), estrone (E₁; 4.6 ± 0.5), estrone sulfate (E₁S; 2.2 ± 0.5), and estradiol-17 α (E₂α; 1.2 ± 0.4). As time proceeded, the relative concentration of E₂α-3S gradually increased so that by 43.2 ± 1.0 min it became the most abundant identifiable metabolite (12.3 ± 1.1) followed by E₂β-3S (9.1 ± 1.7), E₂S (1.2 ± 0.6), E₁ (0.7 ± 0.4) and E₂α (0.3 ± 0.2). These findings are consistent with the view that one of the major pathways of E₂β metabolism in the circulation of the hen is via E₂β

E₂β?3S ?E₁S

E₂α-3S.     

Insular and disjunct distribution of the Arctic wolf in Greenland, 1978�C1998

Little research has been conducted on the spatial and temporal distribution of wolves in the High Arctic, and the processes that influence distributional patterns are not well understood. The present study addressed this information void in north and east Greenland by determining bi-seasonal distribution patterns and core areas based upon 303 sightings of wolves or their tracks during 1978–1998. The data suggested that this wolf population were predominantly distributed in semi-isolated patches in an insular and disjunct distribution. Evidence of wolf occurrence in some areas was so irregular that wolves should be considered absent in most years. Where such areas were clustered over several hundreds of kilometers, they collectively constituted areas of general wolf absence that could be considered gaps in distribution. There was no evidence that this population functioned in a mosaic of closely, interlocking pack territories similar to those reported in lower latitudes. The observed distributional pattern likely reflected the exceptionally impoverished and fragmented polar desert and semi-desert habitat that compelled wolves to adopt differing spatial distribution patterns relative to wolves in temperate areas. The broader scientific significance of this study is that, even in the most remote, vast, and uninhabited regions, it is possible to produce meaningful results on distributional patterns of rare, terrestrial carnivores that can serve as foundation for the next generation of testable hypotheses.     

Effects of parity and periconceptional metabolic state of Holstein–Friesian dams on the glucose metabolism and conformation in their newborn calves

The metabolic state of pregnant mammals influences the offspring’s development and risk of metabolic disease in postnatal life. The metabolic state in a lactating dairy cow differs immensely from that in a non-lactating heifer around the time of conception, but consequences for their calves are poorly understood. The hypothesis of this study was that differences in metabolic state between non-lactating heifers and lactating cows during early pregnancy would affect insulin-dependent glucose metabolism and development in their neonatal calves. Using a mixed linear model, concentrations of glucose, IGF-I and non-esterified fatty acids (NEFAs) were compared between 13 non-lactating heifers and 16 high-yielding dairy cows in repeated blood samples obtained during the 1st month after successful insemination. Calves born from these dams were weighed and measured at birth, and subjected to intravenous glucose and insulin challenges between 7 and 14 days of age. Eight estimators of insulin-dependent glucose metabolism were determined: glucose and insulin peak concentration, area under the curve and elimination rate after glucose challenge, glucose reduction rate after insulin challenge, and quantitative insulin sensitivity check index. Effects of dam parity and calf sex on the metabolic and developmental traits were analysed in a two-way ANOVA. Compared with heifers, cows displayed lower glucose and IGF-I and higher NEFA concentrations during the 1st month after conception. However, these differences did not affect developmental traits and glucose homeostasis in their calves: birth weight, withers height, heart girth, and responses to glucose and insulin challenges in the calves were unaffected by their dam’s parity. In conclusion, differences in the metabolic state of heifers and cows during early gestation under field conditions could not be related to their offspring’s development and glucose homeostasis.     

Bacterial diversity of Escherichia coli in the gut: a reason to re-evaluate probiotic formulations?

Humans and animals are increasingly being subjected to various probiotic formulations with the claim of providing a number of health benefits to the consumer. These formulations usually incorporate bacterial consortia comprising of mostly lactic acid bacteria (LAB). Recent studies have shown that strains found in different regions of the gut are genetically different from each other and may therefore have different abilities to interact with bacteria that they come into contact with. Even LAB show differences in their ability to interact, and further, inhibit growth of pathogenic bacteria in vitro due to individual strain differences. If these results are repeatedly shown to be true in future assessments, an evaluation of bacterial consortia used in probiotic formulations may now be necessary. This may have an impact in the way future probiotic formulations are prepared.