Akinetes: Dormant Cells of Cyanobacteria
01 Jan 2010-pp 5-27
TL;DR: This review focuses on akinetes of Nostocales, emphasizing environmental triggers and cellular responses involved in differentiation, maturation, dormancy, and germination of these resting cells and special attention is given to genetic regulation of the differentiation process.
Abstract: Cyanobacteria are an ancient and morphologically diverse group of photosynthetic prokaryotes, which were the first to evolve oxygenic photosynthesis. Cyanobacteria are widely distributed in diversed environments. In the case of members of the orders Nostocales and Stigonematales, their persistence and success were attributed to their ability to form specialized cells: heterocysts, capable of fixing atmospheric nitrogen and spore-like cells, the akinetes. This review focuses on akinetes of Nostocales, emphasizing environmental triggers and cellular responses involved in differentiation, maturation, dormancy, and germination of these resting cells. Morphological and structural changes, variation in akinete composition, and metabolism are summarized. Special attention is given to the genetic regulation of the differentiation process in an attempt to close gaps in our understanding of the dormancy phenomenon in cyanobacteria and to identify open questions for future research.
Citations
More filters
TL;DR: This Review examines how several cyanobacterial eco-physiological traits, specifically, the ability to grow in warmer temperatures; buoyancy; high affinity for, and ability to store, phosphorus; nitrogen-fixation; akinete production; and efficient light harvesting, vary amongst cyanobacteria genera and may enable them to dominate in future climate scenarios.
609 citations
Cites background from "Akinetes: Dormant Cells of Cyanobac..."
...Akinete germination can be activated by increasing light, temperatures, nutrients, or dissolved oxygen (or a combination of these factors; Kaplan-Levy et al., 2010)....
[...]
TL;DR: In this paper, the authors investigated the contribution of temperature and nutrients in promoting phytoplankton and cyanobacterial biovolume in freshwater lakes and found that the interaction between these two factors explained more of the variance in cyanobacteria biovolate than each factor alone.
Abstract: Cyanobacteria are predicted to increase due to climate and land use change. However, the relative importance and interaction of warming temperatures and increased nutrient availability in determining cyanobacterial blooms are unknown. We investigated the contribution of these two factors in promoting phytoplankton and cyanobacterial biovolume in freshwater lakes. Specifically, we asked: (1) Which of these two drivers, temperature or nutrients, is a better predictor of cyanobacterial biovolume? (2) Do nutrients and temperature significantly interact to affect phytoplankton and cyanobacteria, and if so, is the interaction synergistic? and (3) Does the interaction between these factors explain more of the variance in cyanobacterial biovolume than each factor alone? We analyzed data from . 1000 U.S. lakes and demonstrate that in most cases, the interaction of temperature and nutrients was not synergistic; rather, nutrients predominantly controlled cyanobacterial biovolume. Interestingly, the relative importance of these two factors and their interaction was dependent on lake trophic state and cyanobacterial taxon. Nutrients played a larger role in oligotrophic lakes, while temperature was more important in mesotrophic lakes: Only eutrophic and hyper-eutrophic lakes exhibited a significant interaction between nutrients and temperature. Likewise, some taxa, such as Anabaena, were more sensitive to nutrients, while others, such as Microcystis, were more sensitive to temperature. We compared our results with an extensive literature review and found that they were generally supported by previous studies. As lakes become more eutrophic, cyanobacteria will be more sensitive to the interaction of nutrients and temperature, but ultimately nutrients are the more important predictor of cyanobacterial biovolume.
329 citations
Cites background from "Akinetes: Dormant Cells of Cyanobac..."
...…nitrogen (Oliver and Ganf 2000; Reynolds 2006) and the ability to produce dormant cells to survive unfavorable conditions (Bartram and Chorus 1999; Kaplan-Levy et al. 2010) are other physiological adaptations that may provide cyanobacteria a competitive advantage over other phytoplankton…...
[...]
TL;DR: This work summarizes the currently published records on the invasion of two Nostocales genera, Cylindrospermopsis and Aphanizomenon, to lakes and water reservoirs in subtropical and temperate zones.
Abstract: Similar to the increased number of studies on invasive plants and animals in terrestrial and aquatic ecosystems, many reports were recently published on the invasion of Nostocales (cyanobacteria) to freshwater environments worldwide. Invasion and proliferation of Nostocales in new habitats have the potential to significantly alter the structure of the native community and to modify ecosystem functioning. But most importantly, they influence the water quality due to a variety of toxic compounds that some species produce. Therefore a special attention was given to the invasion and persistence of toxic cyanobacteria in many aquatic ecosystems. Here we summarize the currently published records on the invasion of two Nostocales genera, Cylindrospermopsis and Aphanizomenon, to lakes and water reservoirs in subtropical and temperate zones. These invading species possess traits thought to be common to many invasive organisms: high growth rate, high resource utilization efficiency and overall superior competitive abilities over native species when local conditions vary. Assuming that dispersion routes of cyanobacteria have not been changed much in recent decades, their recent establishment and proliferation in new habitats indicate changes in the environment under which they can exploit their physiological advantage over the native phytoplankton population. In many cases, global warming was identified as the major driving force for the invasion of Nostocales. Due to this uncontrollable trend, invasive Nostocales species are expected to maintain their presence in new habitats and further expand to new environments. In other cases, regional changes in nutrient loads and in biotic conditions were attributed to the invasion events.
170 citations
Additional excerpts
...References (1) Neilan et al., 2003; (2) Kaplan-Levy et al., 2010; (3) Wiedner et al., 2007; (4) Suikkanen et al., 2010; (5) Rücker et al., 2009;(6) Padisák, 1997; (7) Isvánovics et al., 2000; (8) Posselt et al., 2009; (9) Hadas et al., submitted; (10) Bar-Yosef et al., 2010; (11) Briand et al.,…...
[...]
TL;DR: The environmental, physiological and molecular adaptations that enable xerotolerant bacteria to survive in environments in which water is scarce are discussed and insights from modern 'omics' technologies are highlighted.
Abstract: Water is vital for many biological processes and is essential for all living organisms. However, numerous macroorganisms and microorganisms have adapted to survive in environments in which water is scarce; such organisms are collectively termed xerotolerant. With increasing global desertification due to climate change and human-driven desertification processes, it is becoming ever more important to understand how xerotolerant organisms cope with a lack of water. In this Review, we discuss the environmental, physiological and molecular adaptations that enable xerotolerant bacteria to survive in environments in which water is scarce and highlight insights from modern 'omics' technologies. Understanding xerotolerance will inform and hopefully aid efforts to regulate and even reverse desertification.
169 citations
TL;DR: In this review, recent advances of the genus Dolichospermum are summarized, including taxonomy, genetics, bloom occurrence, and production of toxin and taste-and-odor compounds.
118 citations
References
More filters
Book•
29 Mar 1996
TL;DR: In this article, the main groups of algae (divisions or phyla) are considered in turn, and the final chapter is a synthesis, in which the phylogeny of the algae is discussed in relation to the evolution of other living organisms.
Abstract: Algae are ubiquitous; a multitude of species ranging from microscopic unicells to gigantic kelps inhabit the world's oceans, freshwater bodies, soils, rocks, and trees, and are responsible for most of the global production of organic matter by photosynthesis They thus play a fundamental role in the world's ecosystems and a reliable and modern introduction to their kaleidoscopic diversity, systematics, and phylogeny is indispensable In this textbook, the main groups of algae (divisions or phyla) are considered in turn Each chapter begins with a summary of the principal characteristics of the group and interesting aspects of ecology and evolution The final chapter is a synthesis, in which the phylogeny of the algae is discussed in relation to the evolution of other living organisms, primarily on the basis of evidence from recent molecular studies This book is the completely revised and updated edition of a highly acclaimed German work, which was heralded for its clarity as well as its breadth and depth of information This new edition takes into account recent reevaluations in algal systematics and phylogeny provided by the powerful techniques of molecular genetics and electron microscopy, as well as more traditional life history studies The book will be appropriate as an undergraduate text and as a reference for professionals in the field
1,455 citations
"Akinetes: Dormant Cells of Cyanobac..." refers background in this paper
...pelagic habitats ( van den Hoek et al. 1998; Adhikary 1996)....
[...]
Book•
28 Feb 1995
TL;DR: This work focuses on the study of the structure and function of the Photosystem II Reaction Center in Cyanobacteria, which consists of Chloroplast Origins and Evolution, and its role in the Evolution of the Universal Enzyme.
Abstract: Preface. Color Plates. 1. Molecular Evolution and Taxonomy of the Cyanobacteria A. Wilmotte. 2. The Oceanic Cyanobacterial Picoplankton N.G. Carr, N.H. Mann. 3. Prochlorophytes: the 'Other' Cyanobacteria? H.C.P. Matthijs, et al. 4. Molecular Biology of Cyanelles W. Loffelhardt, H.J. Bohnert. 5. Chloroplast Origins and Evolution S.E. Douglas. 6. Supramolecular Membrane Organization E. Gantt. 7. Phycobilisome and Phycobiliprotein Structures W.A. Sidler. 8. The Use of Cyanobacteria in the Study of the Structure and Function of Photosystem II B.A. Barry, et al. 9. The Cytochrome b6f Complex T. Kallas. 10. Photosystem I in Cyanobacteria J.H. Golbeck. 11. The F-type ATPase in Cyanobacteria: Pivotal Point in the Evolution of the Universal Enzyme W.D. Frasch. 12. Soluble Electron Transfer Catalysts of Cyanobacteria L.Z. Morand, et al. 13. Cyanobacterial Respiration G. Schmetterer. 14. The Biochemistry and Molecular Regulation of Carbon Dioxide Metabolism in Cyanobacteria F.R. Tabita. 15. Physiological and Molecular Studies on the Response of Cyanobacteria to Changes in the Ambient Inorganic Carbon Concentration A. Kaplan, et al. 16. Assimilatory Nitrogen Metabolism and its Regulation E. Flores, A. Herrero. 17. Biosynthesis of Cyanobacterial Tetrapyrrole Pigments: Hemes, Chlorophylls, and Phycobilins S.I. Beale. 18. Carotenoids in Cyanobacteria J. Hirschberg, D. Chamovitz. 18. Genetic Analysis of Cyanobacteria T. Thiel. 20. The Transcription Apparatus and the Regulation of Transcription Initiation S.E. Curtis, J.A. Martin. 21. The Responses of Cyanobacteria to Environmental Conditions: Light and Nutrients A.R. Grossman, et al. 22. Short-Term and Long-Term Adaptation of the Photosynthetic Apparatus: Homeostatic Properties of Thylakoids Y. Fujita, et al. 23. Light-Responsive Gene Expression and the Biochemistry of the Photosystem II Reaction Center S.S. Golden. 24. Thioredoxins in Cyanobacteria: Structure and Redox Regulation of Enzyme Activity F.K. Gleason. 25. Iron Deprivation: Physiology and Gene Regulation N.A. Straus. 26. The Cyanobacterial Heat-Shock Response and the Molecular Chaperones R. Webb, L.A. Sherman. 27. Heterocyst Metabolism and Development C.P. Wolk, et al. 28. Differentiation of Hormogonia and Relationships with Other Biological Processes N. Tandeau de Marsac. Organism Index. Gene and Gene Product Index. Subject Index.
1,289 citations
TL;DR: Evidence is presented here showing that trehalose has a remarkably high glass-transition temperature (Tg), which makes this sugar useful in stabilization of biomolecules of use in human welfare and may explain the stability and longevity of anhydrobiotes that contain it.
Abstract: Numerous organisms are capable of surviving more or less complete dehydration. A common feature in their biochemistry is that they accumulate large amounts of disaccharides, the most common of which are sucrose and trehalose. Over the past 20 years, we have provided evidence that these sugars stabilize membranes and proteins in the dry state, most likely by hydrogen bonding to polar residues in the dry macromolecular assemblages. This direct interaction results in maintenance of dry proteins and membranes in a physical state similar to that seen in the presence of excess water. An alternative viewpoint has been proposed, based on the fact that both sucrose and trehalose form glasses in the dry state. It has been suggested that glass formation (vitrification) is in itself sufficient to stabilize dry biomaterials. In this review we present evidence that, although vitrification is indeed required, it is not in itself sufficient. Instead, both direct interaction and vitrification are required. Special properties have often been claimed for trehalose in this regard. In fact, trehalose has been shown by many workers to be remarkably (and sometimes uniquely) effective in stabilizing dry or frozen biomolecules, cells, and tissues. Others have not observed any such special properties. We review evidence here showing that trehalose has a remarkably high glass-transition temperature (Tg). It is not anomalous in this regard because it lies at the end of a continuum of sugars with increasing Tg. However, it is unusual in that addition of small amounts of water does not depress Tg, as in other sugars. Instead, a dihydrate crystal of trehalose forms, thereby shielding the remaining glassy trehalose from effects of the added water. Thus under less than ideal conditions such as high humidity and temperature, trehalose does indeed have special properties, which may explain the stability and longevity of anhydrobiotes that contain it. Further, it makes this sugar useful in stabilization of biomolecules of use in human welfare.
1,276 citations
"Akinetes: Dormant Cells of Cyanobac..." refers background in this paper
...Extracellular polysaccharides of desiccation-resistant cyanobacteria in combination with trehalose or sucrose have been shown to stabilize membrane structure (Hill et al. 1997), which could account for an alternative mechanism of desiccation resistance for these sugars, in addition to their role as “chemical chaperones” within the cytoplasm ( Crowe et al. 1998 )....
[...]