41 research outputs found

    The first record of a rare marine tardigrade, Halobiotus crispae Kristensen, 1982 (Eutardigrada : Hypsibiidae), from the Svalbard Archipelago

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    A rare marine tardigrade Halobiotus crispae Kristensen, 1982 was found abundant in intertidal flats at Josephbukta, Bellsund fiord, West Spitsbergen. This is the first record of this species from the Svalbard Archipelago. So far, the species has been found only in seven other localities in the northern hemisphere (between 56^{\circ} and 69^{\circ}N). The present record greatly extends the known geographical range to the north and also indicates a much wider distribution of the species than formerly reported. Moreover, a potential indicative character of this species and of the study area in monitoring climatic changes is discussed

    Diversity and distribution of tardigrades in soils of Edmonson Point (Northern Victoria Land, continental Antarctica)

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    This work contributes to the knowledge on distribution, diversity and ecology of the Antarctic soil biota. Different soil habitats from several ice-free coastal sites were sampled along the Victoria Land across 7° of latitude from 71° to 78°S during five austral summer seasons between 2003/04 and 2011/12. In this paper we report preliminary data on soil tardigrades (water bears) from Edmondson Point, Northern Victoria Land. Tardigrades were found to be present in 23 of the 41 examined soil samples (56%). Their presence was associated exclusively with soil samples collected from bryophytes communities and under cyanobacterial mats, whereas they were completely absent in fellfield and ornithogenic soils. Tardigrades were least numerous among all soil micrometazoans, their abundance in the positive samples was very variable and ranged from 3 to 1824 individuals per 100 g of soil DW. High water content seemed to be the major factor determining occurrence of tardigrades in the soils investigated. On the other hand low water content and toxic compounds from penguin guano seemed to act as a strong constraint on their existence in the Antarctic soils. Taxonomic evaluation of the extracted tardigrades revealed presence of only two species belonging to class Eutardigrada: Acutuncus antarcticus (Richters, 1904) and Milnesium antarcticum Tumanov, 2006. While A. antarcticus has already been reported previously as the most widespread and abundant tardigrade across the Victoria Land, the information on M. antarcticum is novel, both for Victoria Land and the continental Antarctica

    Diversity of microfungi in ornithogenic soils from Beaufort Island, continental Antarctic

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    This paper presents the results of a biodiversity study of microfungi in ornithogenic soils from Beaufort Island (Ross Sea, continental Antarctic). During the 2004/05 austral sum-mer, we sampled a wide range of soil habitats from an abandoned penguin rookeries to examine the biodiversity of soil microfungi. Beaufort Island is predominantly ice and snow covered, isolated, difficult to access and known to have been visited only infre-quently. Warcup's soil plating method was used for fungal cultivation. A total of ten fungal taxa were isolated, consisting of seven ascomycetes, two anamorphic fungi and one yeast. In terms of their thermal classes, a total of four psychrophilic, five psychro-tolerant and 1 mesophilic fungi were isolated. Thelebolus microsporus, Geomyces sp. and Thelebolus sp. were the most common isolated fungi. Internal Transcribed Spacer (ITS) and 18S rDNA sequences were obtained from 17 fungal isolates, confirming their identification as Thelebolus microsporus, Thelebolus sp., Phoma herbarum and Geo-myces sp

    Comparative analysis of Deschampsia antarctica Desv. population adaptability in the natural environment of Admiralty Bay (King George Island, maritime Antarctic)

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    Plants inhabiting extreme environments may possess features allowing them to tolerate sudden abrupt changes in their environment, a phenomenon often known as ‘adaptability.’ However, ability or success in developing adaptability varies among plant populations. Adaptability can be quantified by measuring variation in the response to the same environmental challenges between plant populations. In this study, we evaluate the adaptability of the iconic Antarctic plant, Deschampsia antarctica, based on traits reflecting three levels of organization: the population level (S, D. antarctica land cover), individual level (Ph, biometrics), and cell level (relative DNA content, rcDNA, in cells of the leaf parenchyma). We sampled a total of six D. antarctica populations in the Admiralty Bay region, King George Island (South Shetland Islands, maritime Antarctic), during the austral summer of 2005–2006, and analyzed pairwise interrelations between various indices reflecting plant population adaptability. The results of these pairwise comparisons were then used to estimate a pooled measure of each population’s adaptability, designated as united latent quality indicator (ULQI). Our results demonstrated that the responses of individual adaptability indices were seldom synchronized, although one population from the central part of the Point Thomas oasis did show some degree of synchronicity. This population also demonstrated the highest ULQI, consistent with the relatively favorable microenvironmental conditions at this location. Two other populations located closer to the shoreline also demonstrated detectable synchronicity and moderate levels of ULQI, while the remaining populations revealed no synchronized responses and negative ULQI values. As the ULQI value obtained will be strongly influenced by the conditions experienced by any given population during a particular season, evaluation of population dynamics requires annual monitoring over multiple seasons

    Identification and phenotypic plasticity of Pseudanabaena catenata from the Svalbard archipelago

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    A filamentous benthic cyanobacteria, strain USMAC16, was isolated from the High Arctic Svalbard archipelago, Norway, and a combination of morphological, ultrastructural and molecular characterisation (16S rRNA gene sequence) used to identify to species level. Cell dimensions, thylakoid arrangement and apical cell shape are consistent with the Pseudanabaena genus description. The molecular characterisation of P. catenata gave 100% similarity with Pseudanabaena catenata SAG 1464-1, originally reported from Germany. Strain USMAC16 was cultured under a range of temperature and photoperiod conditions, in solid and liquid media, and harvested at exponential phase to examine its phenotypic plasticity. Under different culture conditions, we observed considerable variations in cell dimensions. The longest cell (5.91±0.13 μm) was observed at 15°C under 12:12 light:dark, and the widest cell (3.24±0.06 μm) at 4°C under 12:12 light: dark in liquid media. The study provides baseline data documenting the morphological variation of P. catenata in response to changing temperature regimes

    Temperature and pH Profiling of Amylase from Antarctic and Arctic Soil Microfungi

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    While diversity studies and screening for enzyme activities are important elements of understanding fungal roles in the soil ecosystem, extracting and purifying the target enzyme from the fungal cellular system is also required to characterize the enzyme. This is, in particular, necessary before developing the enzyme for industrial-scale production. In the present study, partially purified α-amylase was obtained from strains of Pseudogymnoascus sp. obtained from Antarctic and Arctic locations. Partially purified α-amylases from these polar fungi exhibited very similar characteristics, including being active at 15 °C, although having a small difference in optimum pH. Both fungal taxa are good candidates for the potential application of cold-active enzymes in biotechnological industries, and further purification and characterization steps are now required. The α-amylases from polar fungi are attractive in terms of industrial development because they are active at lower temperatures and acidic pH, thus potentially creating energy and cost savings. Furthermore, they prevent the production of maltulose, which is an undesirable by-product often formed under alkaline conditions. Psychrophilic amylases from the polar Pseudogymnoascus sp. investigated in the present study could provide a valuable future contribution to biotechnological applications

    Discovery of cold-active protease from psychrophilic bacteria isolated from Antarctic region for bio-prospecting

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    The Antarctic region is a new frontier as natural sources for bio-prospecting purposes. Its extreme cold temperature may provide unique enzyme characteristics that have valuable potential for industrial and biotechnological applications. This study was designed to discover proteases that are activate and can work at very low temperatures. Soil samples from the Antarctic region were screened for protease activity on skim milk agar at 4°C. Bacteria that showed clear halo zone around the colonies were selected and identified through 16S rDNA sequencing. Out of 35 bacteria, 10 bacteria that showed rapid halo zone formation were selected and further analyzed by enzymatic assay. By using azocasein as a substrate, the reaction was measured using spectrophotometer at OD340 nm. Based on the 16S rDNA sequence, phylogenetic analysis showed that 88% of the bacteria producing protease were from Pseudomonas sp., 9% from Arthrobacter sp. and 3% from Paenibacillus sp. For enzymatic assay analysis, sample SC8 showed the highest protease activity compared to other 10 samples. This preliminary study successfully demonstrated cold active protease producers that can be further investigated for bioprospecting. In future, purification and characterization of this enzyme is required in order to optimize the enzyme activity
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