Life on the Edge-the Biology of Organisms Inhabiting Extreme Environments: An Introduction to the Symposium

Recent Advances in Marine-Derived Compounds as Potent Antibacterial and Antifungal Agents: A Comprehensive Review

The increase in antimicrobial resistance (AMR) in microorganisms is a significant global health concern. Various factors contribute to AMR, including alterations in cell membrane permeability, increased efflux pump activity, enzymatic modification or inactivation of antibiotics, target site changes, alternative metabolic pathways, and biofilm formation. Marine environments, with their extensive biodiversity, provide a valuable source of natural products with a wide range of biological activities. Marine-derived antimicrobial compounds show significant potential against drug-resistant bacteria and fungi. This review discusses the current knowledge on marine natural products such as microorganisms, sponges, tunicates and mollusks with antibacterial and antifungal properties effective against drug-resistant microorganisms and their ecological roles. These natural products are classified based on their chemical structures, such as alkaloids, amino acids, peptides, polyketides, naphthoquinones, terpenoids, and polysaccharides. Although still in preclinical studies, these agents demonstrate promising in vivo efficacy, suggesting that marine sources could be pivotal in developing new drugs to combat AMR, thereby fulfilling an essential medical need. This review highlights the ongoing importance of marine biodiversity exploration for discovering potential antimicrobial agents.

The Cytotoxic Properties of Extreme Fungi's Bioactive Components-An Updated Metabolic and Omics Overview

Fungi are the most diverse living organisms on planet Earth, where their ubiquitous presence in various ecosystems offers vast potential for the research and discovery of new, naturally occurring medicinal products. Concerning human health, cancer remains one of the leading causes of mortality. While extensive research is being conducted on treatments and their efficacy in various stages of cancer, finding cytotoxic drugs that target tumor cells with no/less toxicity toward normal tissue is a significant challenge. In addition, traditional cancer treatments continue to suffer from chemical resistance. Fortunately, the cytotoxic properties of several natural products derived from various microorganisms, including fungi, are now well-established. The current review aims to extract and consolidate the findings of various scientific studies that identified fungi-derived bioactive metabolites with antitumor (anticancer) properties. The antitumor secondary metabolites identified from extremophilic and extremotolerant fungi are grouped according to their biological activity and type. It became evident that the significance of these compounds, with their medicinal properties and their potential application in cancer treatment, is tremendous. Furthermore, the utilization of omics tools, analysis, and genome mining technology to identify the novel metabolites for targeted treatments is discussed. Through this review, we tried to accentuate the invaluable importance of fungi grown in extreme environments and the necessity of innovative research in discovering naturally occurring bioactive compounds for the development of novel cancer treatments.

The Potential of CRISPR/Cas Technology to Enhance Crop Performance on Adverse Soil Conditions

Worldwide food security is under threat in the actual scenery of global climate change because the major staple food crops are not adapted to hostile climatic and soil conditions. Significant efforts have been performed to maintain the actual yield of crops, using traditional breeding and innovative molecular techniques to assist them. However, additional strategies are necessary to achieve the future food demand. Clustered regularly interspaced short palindromic repeat/CRISPR-associated protein (CRISPR/Cas) technology, as well as its variants, have emerged as alternatives to transgenic plant breeding. This novelty has helped to accelerate the necessary modifications in major crops to confront the impact of abiotic stress on agriculture systems. This review summarizes the current advances in CRISPR/Cas applications in crops to deal with the main hostile soil conditions, such as drought, flooding and waterlogging, salinity, heavy metals, and nutrient deficiencies. In addition, the potential of extremophytes as a reservoir of new molecular mechanisms for abiotic stress tolerance, as well as their orthologue identification and edition in crops, is shown. Moreover, the future challenges and prospects related to CRISPR/Cas technology issues, legal regulations, and customer acceptance will be discussed.

Future trends in measuring physiology in free-living animals

Thus far, ecophysiology research has predominantly been conducted within controlled laboratory-based environments, owing to a mismatch between the recording technologies available for physiological monitoring in wild animals and the suite of behaviours and environments they need to withstand, without unduly affecting subjects. While it is possible to record some physiological variables for free-living animals using animal-attached logging devices, including inertial-measurement, heart-rate and temperature loggers, the field is still in its infancy. In this opinion piece, we review the most important future research directions for advancing the field of 'physiologging' in wild animals, including the technological development that we anticipate will be required, and the fiscal and ethical challenges that must be overcome. Non-invasive, multi-sensor miniature devices are ubiquitous in the world of human health and fitness monitoring, creating invaluable opportunities for animal and human physiologging to drive synergistic advances. We argue that by capitalizing on the research efforts and advancements made in the development of human wearables, it will be possible to design the non-invasive loggers needed by ecophysiologists to collect accurate physiological data from free-ranging animals ethically and with an absolute minimum of impact. In turn, findings have the capacity to foster transformative advances in human health monitoring. Thus, we invite biomedical engineers and researchers to collaborate with the animal-tagging community to drive forward the advancements necessary to realize the full potential of both fields. This article is part of the theme issue 'Measuring physiology in free-living animals (Part II)'.

Viruses in Extreme Environments, Current Overview, and Biotechnological Potential

Virus research has advanced significantly since the discovery of the tobacco mosaic virus (TMV), the characterization of its infection mechanisms and the factors that determine their pathogenicity. However, most viral research has focused on pathogenic viruses to humans, animals and plants, which represent only a small fraction in the virosphere. As a result, the role of most viral genes, and the mechanisms of coevolution between mutualistic viruses, their host and their environment, beyond pathogenicity, remain poorly understood. This review focuses on general aspects of viruses that interact with extremophile organisms, characteristics and examples of mechanisms of adaptation. Finally, this review provides an overview on how knowledge of extremophile viruses sheds light on the application of new tools of relevant use in modern molecular biology, discussing their value in a biotechnological context.

Bacterial Communities of Novaya Zemlya Archipelago Ice and Permafrost

The study of bacterial communities associated with extreme ecosystems is one of the most important tasks in modern microbial ecology. Despite a large number of studies being performed, the ecosystems that have not been sufficiently explored from the microbiological point of view still exist. Such research is needed for improving the understanding of the limits and mechanisms of bacterial survival under extreme conditions, and for revealing previously undescribed species and their role in global biospheric processes and their functional specifics. The results of the complex microbiological characteristics of permafrost and ice—collected on the Severniy Island in the northern part of the Novaya Zemlya archipelago—which have not previously been described from microbiological point of view, are presented in this article. The analysis included both culture-independent and culture-dependent methods, in particular, the spectra of metabolic activity range analysis in vitro under different temperature, pH and salinity conditions. High values for the total number of prokaryotes in situ (1.9 × 108–3.5 × 108 cells/g), a significant part of which was able to return to a metabolically active state after thawing, and moderate numbers of culturable bacteria (3.3 × 106–7.8 × 107 CFU/g) were revealed. Representatives of Proteobacteria, Actinobacteria, and Bacteroidetes were dominant in situ; Actinobacteria, Firmicutes, Proteobacteria, and Bacteroidetes were the most abundant phyla in vitro. Physiological assays revealed the mesophilic and neutrophilic optima of temperature and pH of culturing conditions, respectively, and wide temperature and pH ranges of culturable communities’ reproduction activity. Isolated strains were characterized by moderate halotolerant properties and antibiotic resistance, including multiple antibiotic resistance. It was found that almost all cultured bacterial diversity revealed (not just a few resistant species) had extremotolerant properties regarding a number of stress factors. This indicates the high adaptive potential of the studied microbial communities and their high sustainability and capability to retain functional activity under changing environmental (including climatic) conditions in wide ranges.

Low redundancy and complementarity shape ecosystem functioning in a low-diversity ecosystem

Ecosystem functioning is positively linked to biodiversity on land and in the sea. In high-diversity systems (e.g. coral reefs), species coexist by sharing resources and providing similar functions at different temporal or spatial scales. How species combine to deliver the ecological function they provide is pivotal for maintaining the structure, functioning and resilience of some ecosystems, but the significance of this is rarely examined in low-diversity systems such as estuaries. We tested whether an ecological function is shaped by biodiversity in a low-diversity ecosystem by measuring the consumption of carrion by estuarine scavengers. Carrion (e.g. decaying animal flesh) is opportunistically fed on by a large number of species across numerous ecosystems. Estuaries were chosen as the model system because carrion consumption is a pivotal ecological function in coastal seascapes, and estuaries are thought to support diverse scavenger assemblages, which are modified by changes in water quality and the urbanization of estuarine shorelines. We used baited underwater video arrays to record scavengers and measure the rate at which carrion was consumed by fish in 39 estuaries across 1,000 km of coastline in eastern Australia. Carrion consumption was positively correlated with the abundance of only one species, yellowfin bream Acanthopagrus australis, which consumed 58% of all deployed carrion. The consumption of carrion by yellowfin bream was greatest in urban estuaries with moderately hardened shorelines (20%-60%) and relatively large subtidal rock bars (>0.1 km² ). Our findings demonstrate that an ecological function can be maintained across estuarine seascapes despite both limited redundancy (i.e. dominated by one species) and complementarity (i.e. there is no spatial context where the function is delivered significantly when yellowfin bream are not present) in the functional traits of animal assemblages. The continued functioning of estuaries, and other low-diversity ecosystems, might therefore not be tightly linked to biodiversity, and we suggest that the preservation of functionally dominant species that maintain functions in these systems could help to improve conservation outcomes for coastal seascapes.

Newly Identified Nematodes from Mono Lake Exhibit Extreme Arsenic Resistance

Extremophiles have much to reveal about the biology of resilience, yet their study is limited by sampling and culturing difficulties [1-3]. The broad success and small size of nematodes make them advantageous for tackling these problems [4-6]. We investigated the arsenic-rich, alkaline, and hypersaline Mono Lake (CA, US) [7-9] for extremophile nematodes. Though Mono Lake has previously been described to contain only two animal species (brine shrimp and alkali flies) in its water and sediments [10], we report the discovery of eight nematode species from the lake, including microbe grazers, parasites, and predators. Thus, nematodes are the dominant animals of Mono Lake in species richness. Phylogenetic analysis suggests that the nematodes originated from multiple colonization events, which is striking, given the young history of extreme conditions at Mono Lake [7, 11]. One species, Auanema sp., is new, culturable, and survives 500 times the human lethal dose of arsenic. Comparisons to two non-extremophile sister species [12] reveal that arsenic resistance is a common feature of the genus and a preadaptive trait that likely allowed Auanema to inhabit Mono Lake. This preadaptation may be partly explained by a variant in the gene dbt-1 shared with some Caenorhabditis elegans natural populations and known to confer arsenic resistance [13]. Our findings expand Mono Lake's ecosystem from two known animal species to ten, and they provide a new system for studying arsenic resistance. The dominance of nematodes in Mono Lake and other extreme environments and our findings of preadaptation to arsenic raise the intriguing possibility that nematodes are widely pre-adapted to be extremophiles.