Mycosporines in Extremophilic Fungi—Novel Complementary Osmolytes?

2006 ◽  
Vol 3 (2) ◽  
pp. 105 ◽  
Author(s):  
Tina Kogej ◽  
Cene Gostinčar ◽  
Marc Volkmann ◽  
Anna A. Gorbushina ◽  
Nina Gunde-Cimerman
Keyword(s):  
High Performance ◽  
Extreme Environments ◽  
Growth Conditions ◽  
Black Yeasts ◽  
The Arctic ◽  
Glacial Ice ◽  
Arctic Soil ◽  
Hypersaline Water ◽  
Osmotic Behaviour ◽  
Extremophilic Fungi

Environmental Context.The occurrence of fungi in extreme environments, particularly in hypersaline water and in subglacial ice, is much higher than was previously assumed. When glacial ice melts as a result of calving or surface ablations, these organisms are released in the Arctic soil or sea and have a yet uninvestigated impact on the environment. Knowledge of the metabolites of these extremophilic fungi is important because they could provide signature molecules in the environment, but they can also contribute nutrients to the otherwise oligotrophic polar conditions. In the present work, we examine the osmotic behaviour of fungi grown under hypersaline conditions. Abstract.Fungi isolated from hypersaline waters and polar glacial ice were screened for the presence of mycosporines and mycosporine-like amino acids under non-saline and saline growth conditions. Two different mycosporines and three unidentified UV-absorbing compounds were detected by high performance liquid chromatography in fungal isolates from hypersaline waters and polar glacial ice. It was shown for the first time that the mycosporine–glutaminol–glucoside in halophilic and halotolerant black yeasts from salterns was higher on saline growth medium. This substance might act as a supplementary compatible solute in some extremophilic black yeasts exposed to saline growth conditions.

Growth and Characterization of AllnGaN/InGaN Heterostructures

1996 ◽  
Vol 423 ◽  
Author(s):  
J. C. Roberts ◽  
F. G. Mcintosh ◽  
M. Aumer ◽  
V. Joshkin ◽  
K. S. Boutros ◽  
...  
Keyword(s):  
High Performance ◽  
Visible Spectrum ◽  
Growth Conditions ◽  
Light Emitting ◽  
Mocvd Growth ◽  
Near Ultraviolet ◽  
Active Layers ◽  
Double Heterostructures ◽  
Lattice Matched

AbstractThe emission wavelength of the InxGa1−xN ternary system can span from the near ultraviolet through red regions of the visible spectrum. High quality double heterostructures with these InxGa1−xN active layers are essential in the development of efficient optoelectronic devices such as high performance light emitting diodes and laser diodes. We will report on the MOCVD growth and characterization of thick and thin InGaN films. Thick InxGa1−xN films with values of x up to 0.40 have been deposited and their photoluminescence (PL) spectra measured. AlGaN/InGaN/AlGaN double heterostructures (DHs) have been grown that exhibit PL emission in the violet, blue, green and yellow spectral regions, depending on the growth conditions of the thin InGaN active layer. Preliminary results of an AllnGaN/InGaN/AllnGaN DH, with the potential of realizing a near-lattice matched structure, will also be presented.

Identification and analysis of two sequences encoding ice-binding proteins obtained from a putative bacterial symbiont of the psychrophilic Antarctic ciliate Euplotes focardii

2014 ◽  
Vol 26 (5) ◽  
pp. 491-501 ◽  
Author(s):  
Sandra Pucciarelli ◽  
Federica Chiappori ◽  
Raghul Rajan Devaraj ◽  
Guang Yang ◽  
Ting Yu ◽  
...  
Keyword(s):  
Amino Acid Level ◽  
Bacterial Symbiont ◽  
The Arctic ◽  
Glacial Ice ◽  
Mould Fungus ◽  
Lake Vostok ◽  
Ice Binding ◽  
Stigmatella Aurantiaca ◽  
Ice Binding Protein ◽  
The Antarctic

AbstractWe identified two ice-binding protein (IBP) sequences, named EFsymbAFP and EFsymbIBP, from a putative bacterial symbiont of the Antarctic psychrophilic ciliate Euplotes focardii. EFsymbAFP is 57.43% identical to the antifreeze protein (AFP) from the Stigmatella aurantiaca strain DW4/3-1, which was isolated from the Victoria Valley lower glacier. EFsymbIBP is 53.38% identical to the IBP from the Flavobacteriaceae bacterium strain 3519-10, isolated from the glacial ice of Lake Vostok. EFsymbAFP and EFsymbIBP are 31.73% identical at the amino acid level and are organized in tandem on the bacterial chromosome. The relatively low sequence identity and the tandem organization, which appears unique to this symbiont, suggest an occurrence of horizontal gene transfer (HGT). Structurally, EFsymbAFP and EFsymbIBP are similar to the AFPs from the snow mould fungus Typhula ishikariensis and from the Arctic yeast Leucosporidium sp. AY30. A phylogenetic analysis showed that EFsymbAFP and EFsymbIBP cluster principally with the IBP sequences from other Antarctic bacteria, supporting the view that these sequences belong to an Antarctic symbiontic bacterium of E. focardii. These results confirm that IBPs have a complex evolutionary history, which includes HGT events, most probably due to the demands of the environment and the need for rapid adaptation.

scholarly journals Determination of Caffeine Content in Tea and Maté Tea by using Different Methods

2009 ◽  
Vol 27 (Special Issue 1) ◽  
pp. S213-S216 ◽  
Author(s):  
D. Komes ◽  
D. Horžić ◽  
A. Belščak ◽  
K. Kovačević Ganič ◽  
A. Baljak
Keyword(s):  
Antioxidant Capacity ◽  
High Performance ◽  
Antioxidant Properties ◽  
Growth Conditions ◽  
Hplc Method ◽  
Frap Assay ◽  
Chromatography Method ◽  
Antioxidant Power ◽  
Pharmaceutical Industries ◽  
Mate Tea

Caffeine-containing products have been consumed for hundreds of years for their pleasant flavor and stimulating effects. In recent years, caffeine received increasing attention in food and pharmaceutical industries, due to its pharmacological properties which comprise stimulation of the central nervous system, peripheral vasoconstriction, relaxation of the smooth muscle and myocardial stimulation. The aim of this study was to determine the content of caffeine in five types of tea (white, yellow, green, oolong, black) and two types of maté tea (green maté and roasted maté tea). The content of caffeine was determined by using four different methods: extraction with chloroform, micromethod, method with lead-acetate and high performance liquid chromatography method (HPLC-PDA). The antioxidant capacity of teas as well as of the extracted (“raw”) caffeine was determined by using two methods: reactions with 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) radical (ABTS assay) and Ferric reducing antioxidant power (FRAP assay). The content of caffeine has been associated with plant origin and growth conditions, as well as processing conditions. By applying all four methods, the highest content of caffeine was determined in white tea, whereas maté and roasted maté tea were characterised with the lowest content of caffeine. Spectrophotometric micro-method has proven to be the best alternative to the HPLC method. The highest antioxidant capacity was determined in yellow tea, while the lowest was determined in roasted maté tea. In comparison to the antioxidant capacity of teas, the antioxidant capacity of extracted (“raw”) caffeine is almost negligible, and does not contribute to the overall antioxidant properties of tea.

scholarly journals CHEMICAL AND BIOLOGICAL INDICATORS FOR EVALUATION OF ARCTIC SOIL DEGRADATION AND ITS POTENTIAL TO REMEDIATION

2021 ◽  
Vol 29 (1) ◽  
pp. 33-39
Author(s):  
Tatiana S. Smirnova ◽  
Elena A. Mazlova ◽  
Olga A. Kulikova ◽  
Ilya M. Ostrovkin ◽  
Adam M. Gonopolsky ◽  
...  
Keyword(s):  
Biological Indicators ◽  
Climatic Conditions ◽  
Chloride Ions ◽  
The Arctic ◽  
Environmental Damage ◽  
Arctic Zone ◽  
Arctic Soils ◽  
Arctic Soil ◽  
Restoration Ability ◽  
High Concentrations

In recent years, significant efforts have been made to accelerate the economic development of the Arctic zone, leading to intense environmental pollution of this region, accompanied by the significant impact of accumulated environmental damage in the region. The solution to these problems is difficult due to the remoteness of these areas and severe climatic conditions. Therefore, it is important to evaluate the potential for restoration of arctic soils. For this purpose, various indicators are used, including biological ones. In the analyzed arctic soil samples, high concentrations of petroleum hydrocarbons (up to 47,000 mg/kg) and chloride-ions (0.10–0.14 wt %) were established. Microbioassay demonstrated a presence of hydrocarbon-oxidizing microorganisms: Penicillium, Azotobacter chroococcum, Bacillus subtilis, Pseudomonas oleovorans. A low enzymatic activity and specific Arctic climate point out a low self-restoration ability of the soil, demonstrated the need for its remediation. The microbioassay with microbial strains identification and soil remediation methods suitable for the Arctic zone were recommended.

scholarly journals Climate change and the Arctic hydrologic cycle as calculated by a global coupled atmosphere–ocean model

1995 ◽  
Vol 21 ◽  
pp. 91-95 ◽  
Author(s):  
James R. Miller ◽  
Gary L. Russell
Keyword(s):  
Arctic Ocean ◽  
River Discharge ◽  
Surface Air Temperature ◽  
Horizontal Resolution ◽  
Ocean Model ◽  
Hydrologic Cycle ◽  
Transient Simulation ◽  
The Arctic ◽  
Glacial Ice ◽  
The Arctic Ocean

A global coupled atmosphere–ocean model is used to examine the hydrologic cycle of the Arctic Ocean. The model has a horizontal resolution of 4° × 5°, nine vertical layers in the atmosphere and 13 in the ocean. River discharge into the Arctic Ocean is included by allowing runoff from each continental grid box to flow downstream according to a specified direction file and a speed that depends on topography. A 74 year control simulation of the present climate is used to examine variability of the hydrologic cycle, including precipitation, sea ice, glacial ice and river discharge. A 74 year transient simulation in which atmospheric CO2increases each year at a compound rate оf 1% is then used to examine potential changes in the hydrologic cycle. Among these changes are a 4°C increase in mean annual surface air temperature in the Arctic Ocean, a decrease in ice cover which begins after 35 years, and increases in river discharge and cloud cover. There is little change in the net difference between precipitation and evaporation. Also in the transient simulation, glacial ice on Greenland decreases relative to the control.

Floating Glacial Ice Caps in the Arctic Ocean

Science ◽  
1975 ◽  
Vol 188 (4193) ◽  
pp. 1116-1118 ◽  
Author(s):  
W. S. Broecker
Keyword(s):  
Arctic Ocean ◽  
The Arctic ◽  
Glacial Ice ◽  
Ice Caps ◽  
The Arctic Ocean

scholarly journals Ice Lithologies and Structure of Ice Island Arlis II

1964 ◽  
Vol 5 (37) ◽  
pp. 17-38 ◽  
Author(s):  
David D. Smith
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Fresh Water ◽  
Structural Features ◽  
The Arctic ◽  
Glacial Ice ◽  
Water Ice ◽  
Central Block ◽  
The Arctic Ocean

AbstractIce island ARLIS II, which is adrift in the Arctic Ocean, is a 1.3 km. wide and 3.8 km. long fragment of shelf ice 12–25 m. thick, which preserves several structural features heretofore undescribed in ice. The island is composed of an irregular central block of foliated, locally debris-rich, grey glacial ice bordered in part by extensive areas of stratified bluish sea ice. The central block contains a series of narrow, elongate, sub-parallel dike-like septa of massive fresh-water ice and a large tongue-like body of tightly folded, coarse banded ice. Both the septa and the tongue cut across the foliation and debris zones of the grey ice.The margins of the central block are penetrated by a series of elongate, crudely wedge-shaped re-entrants occupied by salients of bluish sea ice. Two broad, arch-like plunging anticlines deform the stratified sea ice along one margin of the block.The foliation and debris zones in the glacial ice are relict features inherited from the source glacier. The septa formed as crevasse and basal fracture fills. Salients represent fills formed in the irregular re-entrants along the margins of the glacial ice mass. The tongue of tightly folded, banded ice represents an earlier generation salient deformed by compressive forces as the fill built up. The broad anticlines are apparently the result of warping in response to differential ablation but the small, tight plunging folds on their noses and limbs are probably the result of compressive forces.

Holocene Vegetation Change at Treeline North of Yellowknife, Northwest Territories, Canada

1990 ◽  
Vol 34 (2) ◽  
pp. 227-239 ◽  
Author(s):  
K. A. Moser ◽  
G. M. MacDonald
Keyword(s):  
Picea Mariana ◽  
Vegetation Change ◽  
Geographic Location ◽  
The Arctic ◽  
Small Lakes ◽  
Radiocarbon Dates ◽  
Glacial Ice ◽  
Forest Tundra ◽  
Long Wave ◽  
History Of

AbstractTwo radiocarbon-dated cores from small lakes located approximately 25 km north of the mapped boundary between forest-tundra and tundra provide records of postglacial vegetation change at the treeline near Yellowknife, NWT, Canada. Basal radiocarbon dates of 6180 and 7470 yr B.P. were obtained from the cores. The fossil pollen evidence suggests that the initial vegetation wasBetulatundra with a peatland component.Alnusbecame an important constituent of the pollen assemblages between 6900 and 5500 yr B.P. Both lakes record sharp increases inPiceacf.marianapollen at approximately 5000 yr B.P., suggesting the establishment of forest-tundra. By 3500 yr B.P.Picea marianaforest-tundra had withdrawn. The proportion of organic to inorganic sediment in the cores was at a maximum between 5000 and 3500 yr B.P. Tundra has dominated the region since 3500 yr B.P. In northwestern Canada, the maximum northward advance of treeline occurred between 9000 and 5000 yr B.P. The asynchrony in treeline advance in central and northwestern Canada may reflect that glacial ice persisted in the interior NWT longer than previously believed. Alternatively, the asynchronous history of the treeline may be a result of the geometric properties of the long-wave westerly disturbance that is manifest in the median summer position of the arctic front and ultimately controls the geographic location of the treeline.

Methanotrophic diversity in high arctic wetlands on the islands of Svalbard (Norway) - denaturing gradient gel electrophoresis analysis of soil DNA and enrichment cultures

2003 ◽  
Vol 49 (10) ◽  
pp. 602-612 ◽  
Author(s):  
Ingvild Wartiainen ◽  
Anne Grethe Hestnes ◽  
Mette M Svenning
Keyword(s):  
Methane Emission ◽  
Gel Electrophoresis ◽  
Denaturing Gradient Gel Electrophoresis ◽  
The Arctic ◽  
Rrna Gene ◽  
Climatic Warming ◽  
Soil Dna ◽  
Enrichment Cultures ◽  
Arctic Soil ◽  
Gradient Gel Electrophoresis

The methanotrophic community in arctic soil from the islands of Svalbard, Norway (78°N) was analysed by combining group-specific PCR with PCR of the highly variable V3 region of the 16S rRNA gene and then by denaturing gradient gel electrophoresis (DGGE). Selected bands were sequenced for identification. The analyses were performed with DNA extracted directly from soil and from enrichment cultures at 10 and 20 °C. The two genera Methylobacter and Methylosinus were found in all localities studied. The DGGE band patterns were simple, and DNA fragments with single base differences were separated. The arctic tundra is a potential source of extensive methane emission due to climatic warming because of its large reservoirs of stored organic carbon. Higher temperatures due to climatic warming can cause increased methane production, and the abundance and activity of methane-oxidizing bacteria in the arctic soil may be important regulators for methane emission to the atmosphere.Key words: methanotrophic diversity, Svalbard, arctic wetland, denaturing gradient gel electrophoresis.

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