Extremophiles
Dotaz
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elektronický časopis
- Konspekt
- Biologické vědy
- NLK Obory
- biologie
- mikrobiologie, lékařská mikrobiologie
- NLK Publikační typ
- elektronické časopisy
Resistance to adverse conditions is widespread in the microbial world. Microorganisms resistant to ionizing radiation form a technologically interesting but little-explored group. This work focuses on the mechanisms of resistance to radiation in representatives of the Actinobac-teria phylum, both in terms of detoxification mechanisms and in terms of repairing DNA damage.
Intact, growing cells of strongly acidophilic fungi Acidea extrema and Acidothrix acidophila have been successfully transformed by introduction of heterologous DNA fragment (composed of the glyceraldehyde-phosphate-dehydrogenase gene promoter from Emericella nidulans, a metallothionein-coding gene AsMt1 from Amanita strobiliformis and glyceraldehyde-phosphate-dehydrogenase gene terminator from Colletotrichum gloeosporioides) with the length of 1690 bp. The transformation procedure was based on the DNA transfer mediated by Agrobacterium tumefaciens bearing disarmed helper plasmid pMP90 and binary vector pCambia1300 with inserted DNA fragment of interest. The transformants proved to be mitotically stable, and the introduced gene was expressed at least at the level of transcription. Our work confirms that metabolic adaptations of strongly acidophilic fungi do not represent an obstacle for genetic transformation using conventional methods and can be potentially used for production of heterologous proteins. A promising role of the fast growing A. acidophila as active biomass in biotechnological processes is suggested not only by the low susceptibility of the culture grown at low pH to contaminations but also by reduced risk of accidental leaks of genetically modified microorganisms into the environment because highly specialized extremophilic fungi can poorly compete with common microflora under moderate conditions.
- MeSH
- Agrobacterium tumefaciens genetika MeSH
- Amanita genetika MeSH
- Ascomycota genetika MeSH
- exprese genu MeSH
- genetické vektory MeSH
- koncentrace vodíkových iontů MeSH
- metalothionein genetika MeSH
- plazmidy MeSH
- promotorové oblasti (genetika) MeSH
- terminace genetické transkripce MeSH
- transformace genetická * MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Differences in the level of cold acclimation and cryoprotection estimated as ice nucleation activity in snow algae (Chlamydomonas cf. nivalis and Chloromonas nivalis), lichen symbiotic algae (Trebouxia asymmetrica, Trebouxia erici and Trebouxia glomerata), and a mesophilic strain (Chlamydomonas reinhardti) were evaluated. Ice nucleation activity was measured using the freezing droplet method. Measurements were performed using suspensions of cells of A750 (absorbance at 750 nm) ~ 1, 0.1, 0.01 and 0.001 dilutions for each strain. The algae had lower ice nucleation activity, with the exception of Chloromonas nivalis contaminated by bacteria. The supercooling points of the snow algae were higher than those of lichen photobionts. The supercooling points of both, mesophilic and snow Chlamydomonas strains were similar. The lower freezing temperatures of the lichen algae may reflect either the more extreme and more variable environmental conditions of the original localities or the different cellular structure of the strains examined.
Fungi from extreme environments, including acidophilic ones, belong to biotechnologically most attractive organisms. They can serve as a source of enzymes and metabolites with potentially uncommon properties and may actively participate within bioremediation processes. In respect of their biotechnological potential, extremophilic fungi are mostly studied as individual species. Nevertheless, microorganisms rarely live separately and they form biofilms instead. Living in biofilms is the most successful life strategy on the Earth and the biofilm is the most abundant form of life in extreme environments including highly acidic ones. Compared to bacterial fraction, fungal part of acidophilic biofilms represents a largely unexplored source of organisms with possible use in biotechnology and especially data on biofilms of highly acidic soils are missing. The functioning of the biofilm results from interactions between organisms whose metabolic capabilities are efficiently combined. When we look on acidophilic fungi and their biotechnological potential we should take this fact into account as well. The practical problem to be resolved in connection with extensive studies of exploitable properties and abilities of acidophilic fungi is the methodology of isolation of strains from the nature. In this respect, novel isolation techniques should be developed.
In recent years, extremophilic microorganisms have been employed as producers of the microbial bioplastics polyhydroxyalkanoates (PHA), which are of great biotechnological value. Nevertheless, cold-loving or psychrophilic (cryophilic) bacteria have been neglected in this regard. Here, we present an investigation of the Arctic glacier-derived PHA producer Acidovorax sp. A1169. Biolog GEN III Microplates were used as a screening tool to identify the most suitable carbon substrate concerning PHA synthesis. The strain produced homopolymer poly(3-hydroxybutyrate) (PHB) most efficiently (2 g/L) at a temperature of 15 °C when supplied with fructose or mannitol as carbon sources with a substantial decrease of PHB biosynthesis at 17.5 °C. The PHB yield did not increase considerably or even decreased when carbon source concentration exceeded 10 g/L hinting that the strain is oligotrophic in nature. The strain was also capable of introducing 3-hydroxyvalerate (3HV) into the polymer structure, which is known to improve PHA thermoplastic properties. This is the first investigation providing insight into a PHA biosynthesis process by means of a true psychrophile, offering guidelines on polar-region bacteria cultivation, production of PHA and also on the methodology for genetic engineering of psychrophiles.
- MeSH
- Comamonadaceae * genetika MeSH
- genetické inženýrství MeSH
- polyhydroxyalkanoáty * MeSH
- teplota MeSH
- uhlík MeSH
- Publikační typ
- časopisecké články MeSH
We explored the use of Raman spectroscopy to detect organic osmotic solutes as biomarkers in the moderately halophilic heterotrophic bacterium Halomonas elongata grown in complex medium (accumulation of glycine betaine) and in defined medium with glucose as carbon source (biosynthesis of ectoine), and in the anoxygenic phototrophic Ectothiorhodospira marismortui known to synthesize glycine betaine in combination with minor amounts of trehalose and N-α-carbamoyl glutamineamide. We tested different methods of preparation of the material: lyophilization, two-phase extraction of water-soluble molecules, and perchlorate extraction. Raman signals of glycine betaine and ectoine were detected; perchlorate extraction followed by desalting the extract on an ion retardation column gave the best results. Lyophilized cells of E. marismortui showed strong signals of carotenoid pigments, and glycine betaine could be detected only after perchlorate extraction and desalting. The data presented show that Raman spectroscopy is a suitable tool to assess the mode of osmotic adaptation used by halophilic microorganisms.
A wide variety of microhabitats within the extremely acidic abandoned underground copper mine Zlaté Hory (Czech Republic) was investigated. SSU rDNA libraries were analyzed from 15 samples representing gossan, sulfide-leaching environments in the oxidation zone, and acidic water springs in the mine galleries. Microbial analyses were extended by analyses of chemical composition of water and solid phases and identification of arising secondary minerals. The microbial communities of the three main classes of microenvironments differed in almost every aspect. Among others, ecological partitioning of Acidithiobacillus ferrooxidans and the recently described A. ferrivorans was observed. Distinct types of communities inhabiting the water springs were detected. The more extreme springs (pH <3, conductivity >2 mS/cm) were inhabited by "Ferrovum" spp. and A. ferrivorans, whereas Gallionella sp. dominated the less extreme ones. A new role for gossan in the extremely acidic ecosystem is proposed. This zone was inhabited by a large diversity of neutrophilic heterotrophs that appeared to be continuously washed out to the acidic environments localized downstream. Five species originating in gossan were found in several acidic habitats. Here they can survive and probably serve as scavengers of dead biomass, particularly from chemoautotrophic growths. No such process has been described from acidic mine environments so far.
- MeSH
- Acidithiobacillus genetika izolace a purifikace MeSH
- Bacteria genetika izolace a purifikace MeSH
- bakteriální geny MeSH
- biodiverzita MeSH
- ekosystém * MeSH
- fylogeneze MeSH
- Gallionellaceae genetika izolace a purifikace MeSH
- geny rRNA MeSH
- geologické sedimenty chemie mikrobiologie MeSH
- hornictví MeSH
- koncentrace vodíkových iontů MeSH
- minerály MeSH
- sulfidy MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Česká republika MeSH
Biofilm formation is a typical life strategy used by microorganisms populating acidic water systems. The same strategy might be used by microbes in highly acidic soils that are, however, neglected in this regard. In the present study, the microbial community in such highly acidic soil in the Soos National Nature Reserve (Czech Republic) has been investigated using high-throughput DNA sequencing and the organisms associated with biofilm life mode and those preferring planktonic life were distinguished using the biofilm trap technique. Our data show the differences between biofilm and planktonic microbiota fraction, although the majority of the organisms were capable of using both life modes. The by far most abundant prokaryotic genus was Acidiphilium and fungi were identified among the most abundant eukaryotic elements in biofilm formations. On the other hand, small flagellates from diverse taxonomical groups predominated in plankton. The application of cellulose amendment as well as the depth of sampling significantly influenced the composition of the detected microbial community.
- MeSH
- biofilmy MeSH
- koncentrace vodíkových iontů MeSH
- mikrobiota * MeSH
- plankton * MeSH
- půda MeSH
- půdní mikrobiologie MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Česká republika MeSH
Genotypic and morphological diversity of cyanobacteria in the Rupite hot spring (Bulgaria) was investigated by means of optical microscopy, cultivation, single-cell PCR, and 16S rRNA gene amplicon sequencing. Altogether, 34 sites were investigated along the 71-39 °C temperature gradient. Analysis of samples from eight representative sites shown that Illumina, optical microscopy, and Roche 454 identified 72, 45 and 19% respective occurrences of all cumulatively present taxa. Optical microscopy failed to detect species of minor occurrence; whereas, amplicon sequencing technologies suffered from failed primer annealing and the presence of species with extensive extracellular polysaccharides production. Amplicon sequencing of the 16S rRNA gene V5-V6 region performed by Illumina identified the cyanobacteria most reliably to the generic level. Nevertheless, only the combined use of optical microscopy, cultivation and sequencing methods allowed for reliable estimate of the cyanobacterial diversity. Here, we show that Rupite hot-spring system hosts one of the richest cyanobacterial flora reported from a single site above 50 °C. Chlorogloeopsis sp. was the most abundant at the highest temperature (68 °C), followed by Leptolyngbya boryana, Thermoleptolyngbya albertanoae, Synechococcus bigranulatus, Oculatella sp., and Desertifilum sp. thriving above 60 °C, while Leptolyngbya geysericola, Geitlerinema splendidum, and Cyanobacterium aponinum were found above 50 °C.
