The structure of micromycete complexes in permafrost and cryopegs of the Arctic

A comparative study of the structure of micromycete complexes has been performed. The samples of micromycetes were taken by boring from unique habitats: cryopegs (lenses of non-freezing hypersaline water in ancient permafrost horizons) and permafrost Arctic sediments of different age enclosing these cryopegs. The possibility of characterizing the above habitats by the structure of specific complexes of microscopic fungi using qualitative and quantitative indices at extremely low numbers of these organisms was demonstrated.     

Halo-and psychrotolerant Geomyces fungi from arctic cryopegs and marine deposits

Comparative characterization of Geomyces isolates was performed. The isolates were obtained from Arctic cryopegs and the surrounding ancient marine deposits, from nonsaline permafrost soils, and from temperate environments. Microbiological (cultural and morphological) and molecular criteria were used to confirm the identification of the isolates as Geomyces pannorum. The isolates from cryopegs and surrounding marine deposits were shown to differ from those obtained from nonsaline soils and temperate environments in their ability to grow at negative temperatures (?2°C) under increased salt concentration (10%). The results are discussed in relation to the possible inheritance of the adaptive characteristics acquired in specific environments.     

Biodiversity of cryopegs in permafrost

This study describes the biodiversity of the indigenous microbial community in the sodium-chloride water brines (cryopegs) derived from ancient marine sediments and sandwiched within permafrost 100-120,000 years ago after the Arctic Ocean regression. Cryopegs remain liquid at the in situ temperature of -9 to -11 degrees C and make up the only habitat on the Earth that is characterized by permanently subzero temperatures, high salinity, and the absence of external influence during geological time. From these cryopegs, anaerobic and aerobic, spore-less and spore-forming, halotolerant and halophilic, psychrophilic and psychrotrophic bacteria, mycelial fungi and yeast were isolated and their activity was detected below 0 degrees C.     

Survival of Micromycetes and Actinobacteria under Conditions of Long-Term Natural Cryopreservation

Almost all of the investigated samples of the Arctic and Antarctic permafrost sediments of different genesis with ages from 5–10 thousand to 2–3 million years were found to contain viable micromycete and bacterial cells. The maximum amounts of viable cells of fungi (up to 10⁴CFU/g air-dried sample) and bacteria (up to 10⁷–10⁹CFU/g air-dried sample) were present in fine peaty sediment samples taken from different depths. The identified micromycetes belonged to more than 20 genera of the divisions Basidiomycota, Ascomycota, and Zygomycota, and some represented mitosporic fungi. Thawing the samples at 35 and 52°C allowed the number of detected fungal genera to be increased by more than 30%. Aerobic heterotrophic prokaryotes were dominated by coryneform, nocardioform, and spore-forming microorganisms of the order Actinomycetales.Analysis of the isolated fungi and actinomycetes showed that most of them originated from the microbial communities of ancient terrestrial biocenoses.     

Microbiological analysis of cryopegs from the Varandei Peninsula,Barents Sea

The paper deals with the microbiological characterization of water-saturated horizons in permafrost soils (cryopegs) found on the Varandei Peninsula (Barents Sea coast), 4–20 m deep. The total quantity of bacteria in the water of cryopegs was 3.5 × 10⁸ cells/ml. The population of cultivated aerobic heterotrophic bacteria was 3–4 × 10⁷ cells/ml and the number of anaerobic heterotrophic bacteria varied from 10² to 10⁵ cells/ml depending on cultivation temperature and salinity. Sulfate-reducing bacteria and methanogenic archaea were found as hundreds and tens of cells per ml of water, respectively. A pure culture of a sulfate-reducing strain B15 was isolated from borehole 21 and characterized. Phylogenetic analysis has shown that the new bacterium is a member of the genus Desulfovibrio with Desulfovibrio mexicanus as its closest relative (96.5% similarity). However, the significant phenotypic differences suggest that strain B15 is a new species of sulfate-reducing bacteria.     

The structure of the micromycete complexes of oligotrophic peat deposits in the southern taiga subzone of West Siberia

The analysis of the micromycete complexes of oligotrophic peat deposits in the Vasyugan Marsh by direct count and culture methods showed that the micromycete carbon comprises no more than 3% of the total peat carbon and that the microscopic fungal biomass varies from 2 to 13 tons/hectare, depending on the season and the peat deposit thickness. Fungal spores were found in all layers of the peat deposits, whereas the mycelium was found only in the active peat layer. The high abundance of eukaryotic cells in the peats was due to the presence of yeastlike cells rather than fungal spores. Analyses by culture methods showed that micromycetes were present in all peat layers and that their abundance tended to decrease with depth, except for yeasts, which were uniformly distributed in a vertical direction. The micromycete complexes of the peat deposits were similar in the diversity and abundance of dominant species but differed in the composition of minor species. Peat yeasts were dominated by ascomycetes.     

Interactive effects of wildfire and permafrost on microbial communities and soil processes in an Alaskan black spruce forest

Boreal forests contain significant quantities of soil carbon that may be oxidized to CO₂ given future increases in climate warming and wildfire behavior. At the ecosystem scale, decomposition and heterotrophic respiration are strongly controlled by temperature and moisture, but we questioned whether changes in microbial biomass, activity, or community structure induced by fire might also affect these processes. We particularly wanted to understand whether postfire reductions in microbial biomass could affect rates of decomposition. Additionally, we compared the short‐term effects of wildfire to the long‐term effects of climate warming and permafrost decline. We compared soil microbial communities between control and recently burned soils that were located in areas with and without permafrost near Delta Junction, AK. In addition to soil physical variables, we quantified changes in microbial biomass, fungal biomass, fungal community composition, and C cycling processes (phenol oxidase enzyme activity, lignin decomposition, and microbial respiration). Five years following fire, organic surface horizons had lower microbial biomass, fungal biomass, and dissolved organic carbon (DOC) concentrations compared with control soils. Reductions in soil fungi were associated with reductions in phenol oxidase activity and lignin decomposition. Effects of wildfire on microbial biomass and activity in the mineral soil were minor. Microbial community composition was affected by wildfire, but the effect was greater in nonpermafrost soils. Although the presence of permafrost increased soil moisture contents, effects on microbial biomass and activity were limited to mineral soils that showed lower fungal biomass but higher activity compared with soils without permafrost. Fungal abundance and moisture were strong predictors of phenol oxidase enzyme activity in soil. Phenol oxidase enzyme activity, in turn, was linearly related to both ¹³C lignin decomposition and microbial respiration in incubation studies. Taken together, these results indicate that reductions in fungal biomass in postfire soils and lower soil moisture in nonpermafrost soils reduced the potential of soil heterotrophs to decompose soil carbon. Although in the field increased rates of microbial respiration can be observed in postfire soils due to warmer soil conditions, reductions in fungal biomass and activity may limit rates of decomposition.     

Different mechanisms of the biochemical adaptation of mycelial fungi to temperature stress: Changes in the lipid composition

A comparative study was conducted concerning the effect of temperature stress on the lipid composition of representatives of the subkingdomsEomycota andNeomycota. Changes in the composition of lipid acyl chains (such as saturation and desaturation, isomerization, and changes in the length of fatty acid carbon chains), in the phospholipid composition, and in the contents of sterols and other neutral lipids were revealed. Hyperthermia resulted in (i) an increase in the phosphatidylcholine level, (ii) a decrease in the phosphatidylethanolamine level, (iii) a rise in the content of reserve lipids (triacylglycerols), and (iv) a decline in the free fatty acid level in the neutral lipids. An inverse pattern occurred under hypothermic conditions. The peculiarities in the patterns of the temperature adaptation-related changes in the lipid bilayer composition are considered in terms of the systematic position of the fungi.     

Biogeochemistry of methane and methanogenic archaea in permafrost

This study summarizes the findings of our research on the genesis of methane, its content and distribution in permafrost horizons of different age and origin. Supported by reliable data from a broad geographical sweep, these findings confirm the presence of methane in permanently frozen fine-grained sediments. In contrast to the omnipresence of carbon dioxide in permafrost, methane-containing horizons (up to 40.0 mL kg(-1)) alternate with strata free of methane. Discrete methane-containing horizons representing over tens of thousands of years are indicative of the absence of methane diffusion through the frozen layers. Along with the isotopic composition of CH(4) carbon (delta(13)C -64 per thousand to -99 per thousand), this confirms its biological origin and points to in situ formation of this biogenic gas. Using (14)C-labeled substrates, the possibility of methane formation within permafrost was experimentally shown, as confirmed by delta(13)C values. Extremely low values (near -99 per thousand) indicate that the process of CH(4) formation is accompanied by the substantial fractionation of carbon isotopes. For the first time, cultures of methane-forming archaea, Methanosarcina mazei strain JL01 VKM B-2370, Methanobacterium sp. strain M2 VKM B-2371 and Methanobacterium sp. strain MK4 VKM B-2440 from permafrost, were isolated and described.     

The possibility of using cyanobacterial bloom materials as a medium for white rot fungi

Aims: The present study was conducted to evaluate the possibility of using cyanobacterial bloom materials as a medium for white rot fungi and the capability of white rot fungi, Trichaptum abietinum 1302BG and Lopharia spadicea to biodegrade dried cyanobacterial bloom material taken from Taihu Lake. Methods and Results: The results showed T. abietinum 1302BG and L. spadicea could use the cyanobacterial bloom materials taken from Taihu Lake for growth to measure the mycelial plaque and dry‐weight mycelial pellicles of fungi. The removal rate of dried cyanobacterial bloom materials incubated with white rot fungi is approximately 100%. Conclusions: The cyanobacterial bloom material can be used as a glucose substitute in white rot fungi medium. The white rot fungi, T. abietinum 1302BG and L. spadicea, can also directly decrease the biomass of cyanobacterial bloom material taken from Taihu Lake. Significance and Impact of the Study: Cyanobacterial bloom thrives in eutrophic fresh waters all over the world. Micro‐organisms, particularly fungi, have attracted attention as possible agents for the degradation of phytoplankton species. Dealing with cyanobacterial bloom material as a medium for fungi instead of directly discharging them as organic fertilizers is a new, safe and environmentally friendly approach.     

Fungal lycopene: The biotechnology of its production and prospects for its application in medicine

This article deals with the lycopene of mycelial fungi. It pays special attention to its physical and chemical properties, occurrence in nature, biological functions, and the biotechnology of lycopene production. Data are presented concerning the medically important properties of lycopene and the drug Mycolycopene prepared on its basis. Its prospective use in the therapy of prostate cancers is discussed.     

Bacterial genome replication at subzero temperatures in permafrost

Microbial metabolic activity occurs at subzero temperatures in permafrost, an environment representing ∼25% of the global soil organic matter. Although much of the observed subzero microbial activity may be due to basal metabolism or macromolecular repair, there is also ample evidence for cellular growth. Unfortunately, most metabolic measurements or culture-based laboratory experiments cannot elucidate the specific microorganisms responsible for metabolic activities in native permafrost, nor, can bulk approaches determine whether different members of the microbial community modulate their responses as a function of changing subzero temperatures. Here, we report on the use of stable isotope probing with ¹³C-acetate to demonstrate bacterial genome replication in Alaskan permafrost at temperatures of 0 to −20 °C. We found that the majority (80%) of operational taxonomic units detected in permafrost microcosms were active and could synthesize ¹³C-labeled DNA when supplemented with ¹³C-acetate at temperatures of 0 to −20 °C during a 6-month incubation. The data indicated that some members of the bacterial community were active across all of the experimental temperatures, whereas many others only synthesized DNA within a narrow subzero temperature range. Phylogenetic analysis of ¹³C-labeled 16S rRNA genes revealed that the subzero active bacteria were members of the Acidobacteria, Actinobacteria, Chloroflexi, Gemmatimonadetes and Proteobacteria phyla and were distantly related to currently cultivated psychrophiles. These results imply that small subzero temperature changes may lead to changes in the active microbial community, which could have consequences for biogeochemical cycling in permanently frozen systems.     

寒区生态系统中多年冻土研究进展

近地表面的多年冻土是陆地生态系统重要的组成部分,其研究是生态、水文和工程建设研究者关心的重要议题。气候是多年冻土重要的影响因子,国内外研究中,与气候变化相结合的多年冻土研究是当前研究的重要方面;同时,多年冻土的水文学、生态学意义研究也在广泛开展。我国的多年冻土研究一直与寒区经济建设和开发紧密联系,在冻土分布、类型、温度、冻土退化及冻土区开发利用等方面取得了丰硕的成果。未来还应注重高分辨率冻土分布制图、融深变化的研究,并建立长期的多年冻土变化监测机制,以便更好地研究气候变化下,陆地生态系统对全球变化的响应与反馈。     

冻土甲烷循环微生物群落及其对全球变化的响应

冻土是陆地生态系统中最容易受到全球气候变化影响的碳库,既发挥着碳源又起着碳汇的作用。人们非常关注贮存于冻土中有机碳的最终归宿,是因为全球气候变暖会加快冻土的解冻,释放更多的温室气体（二氧化碳和甲烷）到大气中,从而进一步加剧温室效应。据估计每年从北半球冻原陆地生态系统释放进入大气的甲烷约占全球自然界释放甲烷总量的25%。研究证实冻土生物源甲烷的产生和消耗分别由耐(嗜)低温的产甲烷菌(methanogens)和甲烷氧化菌(methanotrophs)介导。鉴于冻土甲烷循环对全球甲烷平衡的显著作用以及在冻土生物地球化学循环中的重要功能,对介导冻土甲烷循环的产甲烷菌和甲烷氧化菌的研究将有助于更好地评估冻土生态系统对全球气候变化的响应和影响,本文就冻土甲烷循环过程、产甲烷菌、甲烷氧化菌的群落结构、活动、生态功能及其对气候和环境变化的响应机制的最新研究进行综述,以期为我国开展冻土甲烷循环机理研究提供支持。     

青藏高原北部多年冻土退化过程中生态系统的变化特征

多年冻土的发育是青藏高原冻土区生态系统稳定的基础,而多年冻土退化效应是目前青藏高原研究的热点。研究了青藏高原北部多年冻土退化过程中生态系统的变化特征。结果表明:在多年冻土退化的过程中,土壤温度逐渐升高,土壤含水量下降,有机质含量降低,植被类型表现为从沼泽化草甸演替为典型草甸,草原化草甸,最终成为沙化草地,群落植物组成从湿生或中湿生逐渐向中生、中旱生乃至旱生转变,草层高度变矮,植被盖度下降,α和β多样性均表现为先增加后减小,在草原化草甸阶段达到最大;草地植物生物量和载畜能力总体表现为降低趋势,但在典型草甸和草原化草甸之间差异不显著。植被经济类群的变化趋势表现为优良的莎草科和禾本科牧草比例下降,而毒杂草比例显著增加,牧草品质下降,饲用价值降低。     

The fungus Penicillium variabile Sopp 1912 isolated from permafrost deposits as a producer of rugulovasines

It has been established that relict fungi Penicillium variabile Sopp can synthesize clavine alkaloids, rugulovasines A and B, which are revealed in this species for the first time. Submerged cultivation of the strain-producer revealed several microcycles of conidia formation. The synthesis of alkaloids was also of a cyclic character. The synchronism of cyclic rugulovasine biosynthesis and conidia formation was revealed. Zinc ions stimulated fungal growth but had a negative effect on the biosynthesis of rugulovasines.     

Nitrogen retention in the riparian zone of catchments underlain by discontinuous permafrost

1. Riparian zones function as important ecotones that reduce nitrate concentration in groundwater and inputs into streams. In the boreal forest of interior Alaska, permafrost confines subsurface flow through the riparian zone to shallow organic horizons, where plant uptake of nitrate and denitrification are typically high. 2. In this study, riparian zone nitrogen retention was examined in a high permafrost catchment (approximately 53% of land area underlain by permafrost) and a low permafrost catchment (approximately 3%). To estimate the contribution of the riparian zone to catchment nitrogen retention, we analysed groundwater chemistry using an end‐member mixing model. 3. Stream nitrate concentration was over twofold greater in the low permafrost catchment than the high permafrost catchment. Riparian groundwater was not significantly different between catchments, averaging 13 μm overall. Nitrogen retention, measured using the end‐member mixing model, averaged 0.75 and 0.22 mmol N m^?2 day^?1 in low and high permafrost catchments, respectively, over the summer. The retention rate of nitrogen in the riparian zone was 10–15% of the export in stream flow. 4. Our results indicate that the riparian zone functions as an important sink for groundwater nitrate and dissolved organic carbon (DOC). However, differences in stream nitrate and DOC concentrations between catchments cannot be explained by solute inputs from riparian groundwater to the stream and differences between streams are probably attributable to deeper groundwater inputs or flows from springs that bypass the riparian zone.     

Novel halotolerant bacterium from cryopeg in permafrost: Description of <Emphasis Type="Italic">Psychrobacter muriicola</Emphasis> sp. nov.

A novel halotolerant psychrotrophic gram-negative bacterium, strain 2pS, was isolated from lenses of water brine in Arctic permafrost (cryopeg). The optimal growth of the new strain was observed at 16–18°C; the maximal and minimal growth temperatures were 37°C and ?2°C, respectively. The pH growth range was 5.8 to 8.5 (optimum 6.5–7.5) and the range of medium salinity was 0 to 100 g/l (optimum 3–8 g/l NaCl). The strain 2pS did not produce acid from carbohydrates and utilized acetate, yeast extract, pyruvate, glutarate, fumarate, caproate, heptanoate, butyrate, malate, DL-lactate, citrate, L-proline, L-tyrosine, butanol, and dulcitol as the sole carbon and energy sources. The major fatty acids of the cell wall at optimal growth temperature were C_18:1ω7 and C_18:1ω9. The G+C DNA base content was 46.0 mol.%. Phylogenetic analysis of the 16S rRNA gene sequences showed that the studied strain was the closest (97% similarity) to Psychrobacter nivimaris DSM 16093^T, a halotolerant psychrotrophic bacterium isolated from the Arctic sea’s ice. Genotypic and phenotypic differences of the new bacterium from closely related species lead to the conclusion that strain 2pS belongs to a novel species of the genus Psychrobacter: Psychrobacter muriicola sp. nov.     

冻融作用对冻土区微生物生理和生态的影响

不同时空尺度的冻融过程导致冻土温度变化及水的相变和迁移,改变着微生物生境的物理和化学性质。冻融过程可改变细胞内外渗透压平衡,且冰晶生长过程能损伤细胞膜和细胞器。限于营养、氧气等其它极端不利条件,不少细胞逐渐转入休眠状态以度过难关;微生物DNA、蛋白质的合成和能量代谢仅用于维持细胞生存。冻融作用通过改变细胞代谢模式而影响微生物参与的寒区碳氮元素的生物地球化学循环。多年冻土层保存了不同地质时期微生物种群的多样性,作为物理和生物地球化学屏障,可有效削弱地表过程和地壳本底辐射对微生物的影响。在长期的适应过程中,微生物发展了相应的耐受机制,从结构和功能方面,细胞和分子水平上应对冻土环境和冻融过程。这可为寻找地外寒冷星球上可能的生命形式提供一些线索。     

Evaluation of the effect of various methods of oil-polluted soil bioremediation on micromycete complexes

The influence of remediation of oil-contaminated gray forest, dark gray forest, and black soils by biological preparations Bacispecin, Devoroil, and Belvitamil on the population of opportunistic and phytotoxic fungi was studied. It was found that this population increased after oil pollution and decreased after three months of remediation. The latter is a sign of gradual recovery of soil microbiota.