With the advent rise is in urbanization and industrialization, heavy metals (HMs) such as lead (Pb) and cadmium (Cd) contamination have increased considerably. It is among the most recalcitrant pollutants majorly affecting the biotic and abiotic components of the ecosystem like human well-being, animals, soil health, crop productivity, and diversity of prokaryotes (bacteria) and eukaryotes (plants, fungi, and algae). At higher concentrations, these metals are toxic for their growth and pose a significant environmental threat, necessitating innovative and sustainable remediation strategies. Bacteria exhibit diverse mechanisms to cope with HM exposure, including biosorption, chelation, and efflux mechanism, while fungi contribute through mycorrhizal associations and hyphal networks. Algae, especially microalgae, demonstrate effective biosorption and bioaccumulation capacities. Plants, as phytoremediators, hyperaccumulate metals, providing a nature-based approach for soil reclamation. Integration of these biological agents in combination presents opportunities for enhanced remediation efficiency. This comprehensive review aims to provide insights into joint action of prokaryotic and eukaryotic interactions in the management of HM stress in the environment.
- MeSH
- Bacteria * metabolism drug effects MeSH
- Biodegradation, Environmental * MeSH
- Eukaryota metabolism drug effects MeSH
- Fungi metabolism MeSH
- Cadmium * metabolism toxicity MeSH
- Soil Pollutants * metabolism MeSH
- Lead * metabolism toxicity MeSH
- Plants microbiology metabolism MeSH
- Publication type
- Journal Article MeSH
- Review MeSH
Due to their ecological, physiological, and molecular adaptations to low and varying temperatures, as well as varying seasonal irradiances, polar non-marine eukaryotic microalgae could be suitable for low-temperature biotechnology. Adaptations include the synthesis of compounds from different metabolic pathways that protect them against stress. Production of biological compounds and various biotechnological applications, for instance, water treatment technology, are of interest to humans. To select prospective strains for future low-temperature biotechnology in polar regions, temperature and irradiance of growth requirements (Q10 and Ea of 10 polar soil unicellular strains) were evaluated. In terms of temperature, three groups of strains were recognized: (i) cold-preferring where temperature optima ranged between 10.1 and 18.4°C, growth rate 0.252 and 0.344 · d-1 , (ii) cold- and warm-tolerating with optima above 10°C and growth rate 0.162-0.341 · d-1 , and (iii) warm-preferring temperatures above 20°C and growth rate 0.249-0.357 · d-1 . Their light requirements were low. Mean values Q10 for specific growth rate ranged from 0.7 to 3.1. The lowest Ea values were observed on cold-preferring and the highest in the warm-preferring strains. One strain from each temperature group was selected for PN and RD measurements. The PN :RD ratio of the warm-preferring strains was less affected by temperature similarly as Q10 and Ea. For future biotechnological applications, the strains with broad temperature tolerance (i.e., the group of cold- and warm-tolerating and warm-preferring strains) will be most useful.
- MeSH
- Photosynthesis MeSH
- Microalgae * MeSH
- Prospective Studies MeSH
- Soil MeSH
- Temperature MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
Mitogen-activated protein kinase (MAPK) pathways are central cellular signalling mechanisms in all eukaryotes. They are key regulators of the cell cycle and stress responses, yet evolution of MAPK families took markedly different paths in the animal and plant kingdoms. Instead of the characteristic divergence of MAPK types in animals, in plants an expanded network of ERK-like MAPKs has emerged. To gain insight into the early evolution of the plant MAPK family we identified and analysed MAPKs in 13 representative species across green algae, a large and diverse early-diverging lineage within the plant kingdom. Our results reveal that the plant MAPK gene family emerged from three types of progenitor kinases, which are ubiquitously present in algae, implying their formation in an early ancestor. Low number of MAPKs is characteristic across algae, the few losses or duplications are associated with genome complexity rather than habitat ecology, despite the importance of MAPKs in environmental signalling in flowering plants. ERK-type MAPKs are associated with cell cycle regulation in opisthokont models, yet in plants their stress-signalling function is more prevalent. Unicellular microalgae offer an excellent experimental system to study the cell cycle, and MAPK gene expression profiles show CDKB-like peaks around S/M phase in synchronised Chlamydomonas reinhardtii cultures, suggesting their participation in cell cycle regulation, in line with the notion that the ancestral eukaryotic MAPK was a cell cycle regulator ERK-like kinase. Our work also highlights the scarcity of signalling knowledge in microalgae, in spite of their enormous ecological impact and emerging economic importance.
- MeSH
- Algal Proteins metabolism MeSH
- Cell Cycle genetics MeSH
- Chlorophyta enzymology MeSH
- Gene Duplication MeSH
- Phylogeny MeSH
- Genetic Variation MeSH
- Mitogen-Activated Protein Kinases chemistry genetics metabolism MeSH
- Evolution, Molecular * MeSH
- Multigene Family MeSH
- Proteome metabolism MeSH
- Gene Expression Regulation, Plant MeSH
- Plants enzymology MeSH
- Amino Acid Sequence MeSH
- Selection, Genetic MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
The environment of high-altitudinal cold deserts of Western Himalaya is characterized by extensive development of biological soil crusts, with cyanobacteria as dominant component. The knowledge of their taxonomic composition and dependency on soil chemistry and elevation is still fragmentary. We studied the abundance and the phylogenetic diversity of the culturable cyanobacteria and eukaryotic microalgae in soil crusts along altitudinal gradients (4600-5900 m) at two sites in the dry mountains of Ladakh (SW Tibetan Plateau and Eastern Karakoram), using both microscopic and molecular approaches. The effects of environmental factors (altitude, mountain range, and soil physico-chemical parameters) on the composition and biovolume of phototrophs were tested by multivariate redundancy analysis and variance partitioning. Both phylogenetic diversity and composition of morphotypes were similar between Karakorum and Tibetan Plateau. Phylogenetic analysis of 16S rRNA gene revealed strains belonging to at least five genera. Besides clusters of common soil genera, e.g., Microcoleus, Nodosilinea, or Nostoc, two distinct clades of simple trichal taxa were newly discovered. The most abundant cyanobacterial orders were Oscillatoriales and Nostacales, whose biovolume increased with increasing elevation, while that of Chroococales decreased. Cyanobacterial species richness was low in that only 15 morphotypes were detected. The environmental factors accounted for 52 % of the total variability in microbial data, 38.7 % of which was explained solely by soil chemical properties, 14.5 % by altitude, and 8.4 % by mountain range. The elevation, soil phosphate, and magnesium were the most important predictors of soil phototrophic communities in both mountain ranges despite their different bedrocks and origin. The present investigation represents a first record on phylogenetic diversity of the cyanobacterial community of biological soil crusts from Western Himalayas and first record from altitudes over 5000 m.
- MeSH
- Biodegradation, Environmental MeSH
- Biodiversity * MeSH
- Phylogeny * MeSH
- Geologic Sediments analysis microbiology MeSH
- Molecular Sequence Data MeSH
- Altitude MeSH
- Soil chemistry MeSH
- Soil Microbiology * MeSH
- Cyanobacteria classification genetics isolation & purification metabolism MeSH
- Publication type
- Journal Article MeSH
- Geographicals
- Tibet MeSH
ATP sulfurylase (ATPS) catalyzes the first step of sulfur assimilation in photosynthetic organisms. An ATPS type A is mostly present in freshwater cyanobacteria, with four conserved cysteine residues. Oceanic cyanobacteria and most eukaryotic algae instead, possess an ATPS-B containing seven to ten cysteines; five of them are conserved, but only one in the same position as ATPS-A. We investigated the role of cysteines on the regulation of the different algal enzymes. We found that the activity of ATPS-B from four different microorganisms was enhanced when reduced and decreased when oxidized. The LC-MS/MS analysis of the ATPS-B from the marine diatom Thalassiosira pseudonana showed that the residue Cys-247 was presumably involved in the redox regulation. The absence of this residue in the ATPS-A of the freshwater cyanobacterium Synechocystis sp. instead, was consistent with its lack of regulation. Some other conserved cysteine residues in the ATPS from T. pseduonana and not in Synechocystis sp.were accessible to redox agents and possibly play a role in the enzyme regulation. Furthermore, the fact that oceanic cyanobacteria have ATPS-B structurally and functionally closer to that from most of eukaryotic algae than to the ATPS-A from other cyanobacteria suggests that life in the sea or freshwater may have driven the evolution of ATPS.
- MeSH
- Chromatography, Liquid MeSH
- Cysteine metabolism MeSH
- Dithiothreitol pharmacology MeSH
- Microalgae enzymology MeSH
- Models, Molecular MeSH
- Oxidation-Reduction drug effects MeSH
- Peptides chemistry metabolism MeSH
- Amino Acid Sequence MeSH
- Sequence Alignment MeSH
- Sulfate Adenylyltransferase chemistry metabolism MeSH
- Tandem Mass Spectrometry MeSH
- Publication type
- Journal Article MeSH
BACKGROUND: Low iron bioavailability is a common feature of ocean surface water and therefore micro-algae developed original strategies to optimize iron uptake and metabolism. The marine picoeukaryotic green alga Ostreococcus tauri is a very good model for studying physiological and genetic aspects of the adaptation of the green algal lineage to the marine environment: it has a very compact genome, is easy to culture in laboratory conditions, and can be genetically manipulated by efficient homologous recombination. In this study, we aimed at characterizing the mechanisms of iron assimilation in O. tauri by combining genetics and physiological tools. Specifically, we wanted to identify and functionally characterize groups of genes displaying tightly orchestrated temporal expression patterns following the exposure of cells to iron deprivation and day/night cycles, and to highlight unique features of iron metabolism in O. tauri, as compared to the freshwater model alga Chalamydomonas reinhardtii. RESULTS: We used RNA sequencing to investigated the transcriptional responses to iron limitation in O. tauri and found that most of the genes involved in iron uptake and metabolism in O. tauri are regulated by day/night cycles, regardless of iron status. O. tauri lacks the classical components of a reductive iron uptake system, and has no obvious iron regulon. Iron uptake appears to be copper-independent, but is regulated by zinc. Conversely, iron deprivation resulted in the transcriptional activation of numerous genes encoding zinc-containing regulation factors. Iron uptake is likely mediated by a ZIP-family protein (Ot-Irt1) and by a new Fea1-related protein (Ot-Fea1) containing duplicated Fea1 domains. The adaptation of cells to iron limitation involved an iron-sparing response tightly coordinated with diurnal cycles to optimize cell functions and synchronize these functions with the day/night redistribution of iron orchestrated by ferritin, and a stress response based on the induction of thioredoxin-like proteins, of peroxiredoxin and of tesmin-like methallothionein rather than ascorbate. We briefly surveyed the metabolic remodeling resulting from iron deprivation. CONCLUSIONS: The mechanisms of iron uptake and utilization by O. tauri differ fundamentally from those described in C. reinhardtii. We propose this species as a new model for investigation of iron metabolism in marine microalgae.
- MeSH
- Adaptation, Biological MeSH
- Chlorophyta classification genetics metabolism MeSH
- Eukaryota genetics metabolism MeSH
- Photoperiod MeSH
- Phylogeny MeSH
- Phytoplankton genetics metabolism MeSH
- Stress, Physiological MeSH
- Homeostasis MeSH
- Copper metabolism MeSH
- Oxidation-Reduction MeSH
- Gene Expression Regulation radiation effects MeSH
- Plant Proteins genetics metabolism MeSH
- Cluster Analysis MeSH
- Signal Transduction MeSH
- Iron Compounds metabolism MeSH
- Gene Expression Profiling MeSH
- Transcriptome MeSH
- High-Throughput Nucleotide Sequencing MeSH
- Iron metabolism MeSH
- Publication type
- Journal Article MeSH
It is now clear that whole genome duplications have occurred in all eukaryotic evolutionary lineages, and that the vast majority of flowering plants have experienced polyploidisation in their evolutionary history. However, study of genome size variation in microalgae lags behind that of higher plants and seaweeds. In this study, we have addressed the question whether microalgal phylogeny is associated with DNA content variation in order to evaluate the evolutionary significance of polyploidy in the model genus Micrasterias. We applied flow-cytometric techniques of DNA quantification to microalgae and mapped the estimated DNA content along the phylogenetic tree. Correlations between DNA content and cell morphometric parameters were also tested using geometric morphometrics. In total, DNA content was successfully determined for 34 strains of the genus Micrasterias. The estimated absolute 2C nuclear DNA amount ranged from 2.1 to 64.7 pg; intraspecific variation being 17.4-30.7 pg in M. truncata and 32.0-64.7 pg in M. rotata. There were significant differences between DNA contents of related species. We found strong correlation between the absolute nuclear DNA content and chromosome numbers and significant positive correlation between the DNA content and both cell size and number of terminal lobes. Moreover, the results showed the importance of cell/life cycle studies for interpretation of DNA content measurements in microalgae.
- MeSH
- Biological Evolution MeSH
- Chromosomes, Plant genetics MeSH
- Genome Size genetics MeSH
- DNA, Plant genetics MeSH
- Phylogeny MeSH
- Genome, Plant genetics MeSH
- Micrasterias genetics MeSH
- Microalgae genetics MeSH
- Streptophyta genetics MeSH
- DNA Copy Number Variations genetics MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
Freshwater green microalgae are diverse and widely distributed across the globe, yet the population structuring of these organisms is poorly understood. We assessed the degree of genetic diversity and differentiation of the desmid species, Micrasterias rotata. First, we compared the sequences of four nuclear regions (actin, gapC1, gapC2, and oee1) in 25 strains and selected the gapC1 and actin regions as the most appropriate markers for population structure assessment in this species. Population genetic structure was subsequently analyzed, based on seven populations from the Czech Republic and Ireland. Hudson's Snn statistics indicated that nearest-neighbor sequences occurred significantly more frequently within geographical populations than within the wider panmictic population. Moreover, Irish populations consistently showed higher genetic diversity than the Czech samples. These results are in accordance with the unbalanced distribution of alleles in many land plant species; however, the large genetic diversity in M. rotata differs from levels of genetic diversity found in most land plants.
Although phototrophic microbial communities are important components of soils in arid and semi-arid ecosystems around the world, the knowledge of their taxonomic composition and dependency on soil chemistry and vegetation is still fragmentary. We studied the abundance and the diversity of cyanobacteria and eukaryotic microalgae along altitudinal gradients (3,700-5,970 m) at four sites in the dry mountains of Ladakh (Little Tibet, Zanskar Mountains, and Eastern Karakoram), using epifluorescence. The effects of environmental factors (altitude, mountain range, and vegetation type) on soil physico-chemical parameters (pH; texture; organic matter, nitrogen, ammonia, and phosphorus contents; and concentration of chlorophylls and carotenoids) and on the composition and biovolume of phototrophs were tested by multivariate redundancy analysis and variance partitioning. Phototrophs were identified in all collected samples, and phototroph biovolume ranged from 0.08 to 0.32 mm(3) g(-1) dry weight. The dominant component was cyanobacteria, which represented 70.9% to 98.6% of the biovolume. Cyanobacterial species richness was low in that only 28 morphotypes were detected. The biovolume of Oscillatoriales consisted mainly of Phormidium spp. and Microcoleus vaginatus. The environmental factors accounted for 43.8% of the total variability in microbial and soil data, 20.6% of which was explained solely by mountain range, 7.0% by altitude, and 8.4% by vegetation type. Oscillatoriales prevailed in alpine meadows (which had relatively high organic matter and fine soil texture), while Nostocales dominated in the subnival zone and screes. Eukaryotic microalgae together with cyanobacteria in the order Chroococcales were mostly present in the subnival zone. We conclude that the high elevation, semiarid, and arid soils in Ladakh are suitable habitats for microbial phototrophic communities and that the differences in these communities are associated with site, altitude, and vegetation type.
- MeSH
- Chlorophyll analysis MeSH
- Microscopy, Fluorescence methods MeSH
- Phototrophic Processes MeSH
- Microalgae growth & development MeSH
- Multivariate Analysis MeSH
- Altitude MeSH
- Soil chemistry MeSH
- Soil Microbiology MeSH
- Cyanobacteria growth & development MeSH
- Biota MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Geographicals
- Tibet MeSH
Fykotoxiny mořského původu jsou produkovány toxigenními řasami a sinicemi, které představují obvyklou potravu pro řadu mořských živočichů, kteří se pak sami stávají toxickými. V posledních letech jsou předmětem zvýšeného zájmu, zejména proto, že se cestou potravního řetězce dostávají do výrobků z mořských živočichů, a tak působí u lidí onemocnění, která jsou vzhledem k současným znalostem obtížně léčitelná. Riziko onemocnění způsobeného toxigenními řasami a sinicemi vzrůstá vzhledem ke zvýšené migraci obyvatelstva i vzhledem k vysílání vojenských misí do nestabilních oblastí světa. Takové aktivity mohou vyvolat rozsáhlá zdravotní poškození somatického i psychického rázu. Jsou nastíněny možnosti a význam preventivních opatření, jejich dodržování, zvláště pro vojenské mise.
The marine microalgae producing the phycotoxins are common food for many marine animals which then themselves become toxic. In the recent years an enhanced attention has been paid to the phycotoxins because they penetrate into the fishery products through feed chains and they can cause intoxication in humans the therapy of which is very difficult. The danger concerning toxigenic microalgae is growing as a consequence of the enhanced migration of population and military missions into unstable regions of the world. These activities can cause severe health impairment of somatic and psychological character. The possibilities and importance of preventive measures and their observance are outlined particularly for military missions.
- MeSH
- Ciguatoxins isolation & purification toxicity MeSH
- Ethers, Cyclic isolation & purification toxicity MeSH
- Eukaryota chemistry pathogenicity MeSH
- Phytoplankton chemistry pathogenicity MeSH
- Mollusk Venoms isolation & purification toxicity MeSH
- Okadaic Acid isolation & purification toxicity MeSH
- Shellfish toxicity MeSH
- Marine Toxins analysis chemistry toxicity MeSH
- Seafood adverse effects toxicity MeSH
- Proline analogs & derivatives toxicity MeSH
- Saxitoxin isolation & purification toxicity MeSH
- Cyanobacteria chemistry pathogenicity MeSH
- Spiro Compounds isolation & purification toxicity MeSH
- Tetrodotoxin isolation & purification therapeutic use MeSH
