Algal Toxic Compounds and Their Aeroterrestrial, Airborne and other Extremophilic Producers with Attention to Soil and Plant Contamination: A Review

The review summarizes the available knowledge on toxins and their producers from rather disparate algal assemblages of aeroterrestrial, airborne and other versatile extreme environments (hot springs, deserts, ice, snow, caves, etc.) and on phycotoxins as contaminants of emergent concern in soil and plants. There is a growing body of evidence that algal toxins and their producers occur in all general types of extreme habitats, and cyanobacteria/cyanoprokaryotes dominate in most of them. Altogether, 55 toxigenic algal genera (47 cyanoprokaryotes) were enlisted, and our analysis showed that besides the “standard” toxins, routinely known from different waterbodies (microcystins, nodularins, anatoxins, saxitoxins, cylindrospermopsins, BMAA, etc.), they can produce some specific toxic compounds. Whether the toxic biomolecules are related with the harsh conditions on which algae have to thrive and what is their functional role may be answered by future studies. Therefore, we outline the gaps in knowledge and provide ideas for further research, considering, from one side, the health risk from phycotoxins on the background of the global warming and eutrophication and, from the other side, the current surge of interest which phycotoxins provoke due to their potential as novel compounds in medicine, pharmacy, cosmetics, bioremediation, agriculture and all aspects of biotechnological implications in human life.

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Bioactive Molecules from Extreme Environments

Marine Drugs ◽

10.3390/md18120640 ◽

2020 ◽

Vol 18 (12) ◽

pp. 640

Author(s):

Daniela Giordano

Keyword(s):

Hydrothermal Vents ◽

Biological Activities ◽

Extreme Environments ◽

Structural Diversity ◽

Bioactive Molecules ◽

Food Industries ◽

Extreme Habitats ◽

Marine Areas ◽

Harsh Conditions ◽

Huge Variety

Marine organisms inhabiting extreme habitats are a promising reservoir of bioactive compounds for drug discovery. Extreme environments, i.e., polar and hot regions, deep sea, hydrothermal vents, marine areas of high pressure or high salinity, experience conditions close to the limit of life. In these marine ecosystems, “hot spots” of biodiversity, organisms have adopted a huge variety of strategies to cope with such harsh conditions, such as the production of bioactive molecules potentially valuable for biotechnological applications and for pharmaceutical, nutraceutical and cosmeceutical sectors. Many enzymes isolated from extreme environments may be of great interest in the detergent, textile, paper and food industries. Marine natural products produced by organisms evolved under hostile conditions exhibit a wide structural diversity and biological activities. In fact, they exert antimicrobial, anticancer, antioxidant and anti-inflammatory activities. The aim of this Special Issue “Bioactive Molecules from Extreme Environments” was to provide the most recent findings on bioactive molecules as well as enzymes isolated from extreme environments, to be used in biotechnological discovery pipelines and pharmaceutical applications, in an effort to encourage further research in these extreme habitats.

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Characterization of lipopolysaccharide transport protein complex

Open Life Sciences ◽

10.2478/s11535-013-0250-5 ◽

2014 ◽

Vol 9 (2) ◽

pp. 131-138

Author(s):

Quanju Xiang ◽

Haiyan Wang ◽

Zhongshan Wang ◽

Yizheng Zhang ◽

Changjiang Dong

Keyword(s):

Transport Mechanism ◽

Transport Proteins ◽

Gram Negative Bacteria ◽

Inner Membrane ◽

Toxic Compounds ◽

Outer Membranes ◽

Harsh Conditions ◽

Cytoplasmic Side

AbstractLipopolysaccharide (LPS) is an essential component of the outer membranes (OM) of most Gram-negative bacteria, which plays a crucial role in protection of the bacteria from toxic compounds and harsh conditions. The LPS is biosynthesized at the cytoplasmic side of inner membrane (IM), and then transported across the aqueous periplasmic compartment and assembled correctly at the outer membrane. This process is accomplished by seven LPS transport proteins (LptA-G), but the transport mechanism remains poorly understood. Here, we present findings by pull down assays in which the periplasmic component LptA interacts with both the IM complex LptBFGC and the OM complex LptDE in vitro, but not with complex LptBFG. Using purified Lpt proteins, we have successfully reconstituted the seven transport proteins as a complex in vitro. In addition, the LptC may play an essential role in regulating the conformation of LptBFG to secure the lipopolysaccharide from the inner membrane. Our results contribute to the understanding of lipopolysaccharide transport mechanism and will provide a platform to study the detailed mechanism of the LPS transport in vitro.

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Extremophilic Exopolysaccharides: Biotechnologies and Wastewater Remediation

Frontiers in Microbiology ◽

10.3389/fmicb.2021.721365 ◽

2021 ◽

Vol 12 ◽

Author(s):

Aparna Banerjee ◽

Shrabana Sarkar ◽

Tanvi Govil ◽

Patricio González-Faune ◽

Gustavo Cabrera-Barjas ◽

...

Keyword(s):

Hydrothermal Vents ◽

Hot Springs ◽

Mine Drainage ◽

Oil Spills ◽

Extreme Environments ◽

Substantial Part ◽

Wastewater Remediation ◽

Water Contaminants ◽

Chemical Groups ◽

Trace And Toxic Metals

Various microorganisms thrive under extreme environments, like hot springs, hydrothermal vents, deep marine ecosystems, hyperacid lakes, acid mine drainage, high UV exposure, and more. To survive against the deleterious effect of these extreme circumstances, they form a network of biofilm where exopolysaccharides (EPSs) comprise a substantial part. The EPSs are often polyanionic due to different functional groups in their structural backbone, including uronic acids, sulfated units, and phosphate groups. Altogether, these chemical groups provide EPSs with a negative charge allowing them to (a) act as ligands toward dissolved cations as well as trace, and toxic metals; (b) be tolerant to the presence of salts, surfactants, and alpha-hydroxyl acids; and (c) interface the solubilization of hydrocarbons. Owing to their unique structural and functional characteristics, EPSs are anticipated to be utilized industrially to remediation of metals, crude oil, and hydrocarbons from contaminated wastewaters, mines, and oil spills. The biotechnological advantages of extremophilic EPSs are more diverse than traditional biopolymers. The present review aims at discussing the mechanisms and strategies for using EPSs from extremophiles in industries and environment bioremediation. Additionally, the potential of EPSs as fascinating biomaterials to mediate biogenic nanoparticles synthesis and treat multicomponent water contaminants is discussed.

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Phytoplankton in extreme environments: importance and consequences of habitat permanency

Hydrobiologia ◽

10.1007/s10750-020-04353-4 ◽

2020 ◽

Vol 848 (1) ◽

pp. 157-176 ◽

Cited By ~ 1

Author(s):

Judit Padisák ◽

Luigi Naselli-Flores

Keyword(s):

Extreme Environments ◽

Single Species ◽

Physiological Adaptation ◽

Low Light ◽

High Metal Content ◽

Top Predators ◽

Physiological Adaptations ◽

Characteristic Species ◽

Compositional Diversity ◽

Harsh Conditions

AbstractThere is hardly any sunshine exposed surface on this Earth, be it water or terrain, which would not support some biota. Still, many habitats offer harsh conditions requiring specialized physiological adaptations to survive. These environments are referred to as extremes; often inhabited by extremophilic organisms. In this review, characteristic species and assemblage properties of phytoplankton inhabiting extreme environments (especially lakes and pools where planktic life is potentially possible and independently of their origin) in terms of alkalinity, acidity, DOC, salinity, temperature, light and mixing regime will be outlined. Lakes characterized by more than a single extreme are common (e.g. saline + alkaline; acidic + high DOC + high metal content + low light). At the edge of extremes (e.g. pH of 1; salinity over ~ 100–150 g l−1) single species with appropriate physiological adaptation are selected and the phytoplankton is often dominated by a single species (monodominant) setting compositional diversity to zero. Under less extreme conditions permanent equilibria may persist; in many cases over several years in contrast to „average” lakes where equilibria are rare and ephemeral. Food webs depending on „extreme phytoplankton” are often atypical for example because the microbial loop is of prior importance or because birds are top predators.

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Meta-Analysis of Microbial Communities in Hot Springs: Recurrent Taxa and Complex Shaping Factors beyond pH and Temperature

Microorganisms ◽

10.3390/microorganisms8060906 ◽

2020 ◽

Vol 8 (6) ◽

pp. 906 ◽

Cited By ~ 2

Author(s):

Francisco L. Massello ◽

Chia Sing Chan ◽

Kok-Gan Chan ◽

Kian Mau Goh ◽

Edgardo Donati ◽

...

Keyword(s):

Microbial Communities ◽

Metabolic Profile ◽

Hot Springs ◽

Meta Analysis ◽

Extreme Environments ◽

Alpha Diversity ◽

Amplicon Sequencing ◽

Phylogenetic Distance ◽

Microbial Profile ◽

The World

The study of microbial communities from extreme environments is a fascinating topic. With every study, biologists and ecologists reveal interesting facts and questions that dispel the old belief that these are inhospitable environments. In this work, we assess the microbial diversity of three hot springs from Neuquén, Argentina, using high-throughput amplicon sequencing. We predicted a distinct metabolic profile in the acidic and the circumneutral samples, with the first ones being dominated by chemolithotrophs and the second ones by chemoheterotrophs. Then, we collected data of the microbial communities of hot springs around the world in an effort to comprehend the roles of pH and temperature as shaping factors. Interestingly, there was a covariation between both parameters and the phylogenetic distance between communities; however, neither of them could explain much of the microbial profile in an ordination model. Moreover, there was no correlation between alpha diversity and these parameters. Therefore, the microbial communities’ profile seemed to have complex shaping factors beyond pH and temperature. Lastly, we looked for taxa associated with different environmental conditions. Several such taxa were found. For example, Hydrogenobaculum was frequently present in acidic springs, as was the Sulfolobaceae family; on the other hand, Candidatus Hydrothermae phylum was strongly associated with circumneutral conditions. Interestingly, some singularities related to sites featuring certain taxa were also observed.

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Phycobiliproteins from extreme environments and their potential applications

Journal of Experimental Botany ◽

10.1093/jxb/eraa139 ◽

2020 ◽

Vol 71 (13) ◽

pp. 3827-3842 ◽

Cited By ~ 2

Author(s):

Anton Puzorjov ◽

Alistair J McCormick

Keyword(s):

Hot Springs ◽

Elevated Temperatures ◽

Algal Species ◽

Extreme Environments ◽

Fundamental Understanding ◽

Thermophilic Species ◽

Red Algal ◽

Potential Applications ◽

Thermophilic Organisms ◽

Photosynthetic Adaptation

Abstract The light-harvesting phycobilisome complex is an important component of photosynthesis in cyanobacteria and red algae. Phycobilisomes are composed of phycobiliproteins, including the blue phycobiliprotein phycocyanin, that are considered high-value products with applications in several industries. Remarkably, several cyanobacteria and red algal species retain the capacity to harvest light and photosynthesise under highly selective environments such as hot springs, and flourish in extremes of pH and elevated temperatures. These thermophilic organisms produce thermostable phycobiliproteins, which have superior qualities much needed for wider adoption of these natural pigment–proteins in the food, textile, and other industries. Here we review the available literature on the thermostability of phycobilisome components from thermophilic species and discuss how a better appreciation of phycobiliproteins from extreme environments will benefit our fundamental understanding of photosynthetic adaptation and could provide a sustainable resource for several industrial processes.

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Brazilian research on extremophiles in the context of astrobiology

International Journal of Astrobiology ◽

10.1017/s1473550412000249 ◽

2012 ◽

Vol 11 (4) ◽

pp. 325-333 ◽

Cited By ~ 7

Author(s):

Rubens T. D. Duarte ◽

Felipe Nóbrega ◽

Cristina R. Nakayama ◽

Vivian H. Pellizari

Keyword(s):

Hydrothermal Vents ◽

High Pressures ◽

Human Life ◽

Extreme Environments ◽

Brazilian Coast ◽

Polar Regions ◽

Oceanic Sediments ◽

Wide Range ◽

Antarctic Continent ◽

Micro Organisms

AbstractExtremophiles are organisms adapted to grow at extreme ranges of environmental variables, such as high or low temperatures, acid or alkaline medium, high salt concentration, high pressures and so forth. Most extremophiles are micro-organisms that belong to the Archaea and Bacteria domains, and are widely spread across the world, which include the polar regions, volcanoes, deserts, deep oceanic sediments, hydrothermal vents, hypersaline lakes, acid and alkaline water bodies, and other extreme environments considered hostile to human life. Despite the tropical climate, Brazil has a wide range of ecosystems which include some permanent or seasonally extreme environments. For example, the Cerrado is a biome with very low soil pH with high Al+3concentration, the mangroves in the Brazilian coast are anaerobic and saline, Pantanal has thousands of alkaline–saline lakes, the Caatinga arid and hot soils and the deep sea sediments in the Brazilian ocean shelf. These environments harbour extremophilic organisms that, coupled with the high natural biodiversity in Brazil, could be explored for different purposes. However, only a few projects in Brazil intended to study the extremophiles. In the frame of astrobiology, for example, these organisms could provide important models for defining the limits of life and hypothesize about life outside Earth. Brazilian microbiologists have, however, studied the extremophilic micro-organisms inhabiting non-Brazilian environments, such as the Antarctic continent. The experience and previous results obtained from the Brazilian Antarctic Program (PROANTAR) provide important results that are directly related to astrobiology. This article is a brief synopsis of the Brazilian experience in researching extremophiles, indicating the most important results related to astrobiology and some future perspectives in this area.

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Animals in ancient Greek warfare : a study of the elephant, camel, and dog

10.32469/10355/78092 ◽

2020 ◽

Author(s):

◽

Jenna Rae Rice

Keyword(s):

Animal Studies ◽

Extreme Environments ◽

Historical Analysis ◽

Alexander The Great ◽

Ancient Greek ◽

Future Studies ◽

Fresh Perspective ◽

Human Animal ◽

Ancient Warfare ◽

The Military

My dissertation asserts that the study of animals is integral to the thorough understanding of the ancient military landscape, and three animals in particular warrant particular attention: the elephant, camel, and dog. I place these animals into the broader context of ancient warfare through the use of human-animal studies, zoological research, archaeological studies, and careful historical analysis, proving their impact in the Greco Macedonian military. I contend that the war elephant's tactical significance is overstated by modern scholarship and requires a re-evaluation, concluding that due to a combination of physiological and behavioral reasons, elephants were not compatible with Greek military practices. They were, however, compatible with Diadoch politics, and were used by generations of Seleucids and Ptolemies as an emblem of legitimacy, martial strength, and royalty. I consider the military value of the camel within the Greek realm, arguing that it has been largely ignored and requires analysis from a fresh perspective. I use recent zoological studies to argue against scholarship that dismisses the camel's abilities to tolerate extreme environments, and I assess the its value within the army of Alexander the Great through a series of specific case studies. Subsequently, I investigate the use of dogs in the ancient military sphere through a study of literary and archaeological sources. I show how dogs participated both directly in battle (Ionia) and in a more auxiliary fashion as guards, hunters, and companions. Finally, I present a survey of scientific archaeological, and historical studies of the ancient warhorse, considering its status within the scholarly community as a goal and model for future studies of other animals that functioned in the ancient military sphere.

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Microbial diversity of extreme habitats in human homes

PeerJ ◽

10.7717/peerj.2376 ◽

2016 ◽

Vol 4 ◽

pp. e2376 ◽

Cited By ~ 12

Author(s):

Amy M. Savage ◽

Justin Hills ◽

Katherine Driscoll ◽

Daniel J. Fergus ◽

Amy M. Grunden ◽

...

Keyword(s):

Microbial Diversity ◽

High Throughput ◽

High Throughput Sequencing ◽

Extreme Environments ◽

Extreme Temperature ◽

Hot Water ◽

Extreme Conditions ◽

Extreme Temperatures ◽

Environmental Extremes ◽

Extreme Habitats

High-throughput sequencing techniques have opened up the world of microbial diversity to scientists, and a flurry of studies in the most remote and extreme habitats on earth have begun to elucidate the key roles of microbes in ecosystems with extreme conditions. These same environmental extremes can also be found closer to humans, even in our homes. Here, we used high-throughput sequencing techniques to assess bacterial and archaeal diversity in the extreme environments inside human homes (e.g., dishwashers, hot water heaters, washing machine bleach reservoirs, etc.). We focused on habitats in the home with extreme temperature, pH, and chemical environmental conditions. We found a lower diversity of microbes in these extreme home environments compared to less extreme habitats in the home. However, we were nonetheless able to detect sequences from a relatively diverse array of bacteria and archaea. Habitats with extreme temperatures alone appeared to be able to support a greater diversity of microbes than habitats with extreme pH or extreme chemical environments alone. Microbial diversity was lowest when habitats had both extreme temperature and one of these other extremes. In habitats with both extreme temperatures and extreme pH, taxa with known associations with extreme conditions dominated. Our findings highlight the importance of examining interactive effects of multiple environmental extremes on microbial communities. Inasmuch as taxa from extreme environments can be both beneficial and harmful to humans, our findings also suggest future work to understand both the threats and opportunities posed by the life in these habitats.

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Phage Community Dynamics in Hot Springs

Applied and Environmental Microbiology ◽

10.1128/aem.70.3.1633-1640.2004 ◽

2004 ◽

Vol 70 (3) ◽

pp. 1633-1640 ◽

Cited By ~ 105

Author(s):

Mya Breitbart ◽

Linda Wegley ◽

Steven Leeds ◽

Tom Schoenfeld ◽

Forest Rohwer

Keyword(s):

Energy Flow ◽

Community Dynamics ◽

Hot Springs ◽

Hot Spring ◽

Extreme Environments ◽

Turnover Time ◽

Dna Transfer ◽

Thermal Environments ◽

Microbial Food Webs ◽

Population Turnover

ABSTRACT In extreme thermal environments such as hot springs, phages are the only known microbial predators. Here we present the first study of prokaryotic and phage community dynamics in these environments. Phages were abundant in hot springs, reaching concentrations of a million viruses per milliliter. Hot spring phage particles were resistant to shifts to lower temperatures, possibly facilitating DNA transfer out of these extreme environments. The phages were actively produced, with a population turnover time of 1 to 2 days. Phage-mediated microbial mortality was significant, making phage lysis an important component of hot spring microbial food webs. Together, these results show that phages exert an important influence on microbial community structure and energy flow in extreme thermal environments.

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