The brine shrimp Artemia is a micro-crustacean, well adapted to the harsh conditions that severely hypersaline environments impose on survival and reproduction. Adaptation to these conditions has ...taken place at different functional levels or domains, from the individual (molecular-cellular-physiological) to the population level. Such conditions are experienced by very few equivalent macro-planktonic organisms; thus, Artemia can be considered a model animal extremophile offering a unique suite of adaptations that are the focus of this review. The most obvious is a highly efficient osmoregulation system to withstand up to 10 times the salt concentration of ordinary seawater. Under extremely critical environmental conditions, for example when seasonal lakes dry-out, Artemia takes refuge by producing a highly resistant encysted gastrula embryo (cyst) capable of severe dehydration enabling an escape from population extinction. Cysts can be viewed as gene banks that store a genetic memory of historical population conditions. Their occurrence is due to the evolved ability of females to "perceive" forthcoming unstable environmental conditions expressed by their ability to switch reproductive mode, producing either cysts (oviparity) when environmental conditions become deleterious or free-swimming nauplii (ovoviviparity) that are able to maintain the population under suitable conditions. At the population level the trend is for conspecific populations to be fragmented into locally adapted populations, whereas species are restricted to salty lakes in particular regions (regional endemism). The Artemia model depicts adaptation as a complex response to critical life conditions, integrating and refining past and present experiences at all levels of organization. Although we consider an invertebrate restricted to a unique environment, the processes to be discussed are of general biological interest. Finally, we highlight the benefits of understanding the stress response of Artemia for the well-being of human populations.
Hypersaline lakes or brines are unique ecosystems with unique value and biodiversity that provide economic (mining) and noneconomic services (waterbird habitat). As they are shrinking around the ...world due to brine diversion and climatic oscillations, this article alerts on the fragility of Andean high‐altitude hypersaline lagoons in Salar de Atacama in the hyperarid Atacama Desert, northern Chile. As an integral part of the world's largest lithium exploitation from brine pumped from beneath the Salar, brine diversion and water shortage should compromise lagoons structure, functioning, and their high ecological value as habitat for endangered migratory birds like flamingos. Conserving the unique biodiversity and properties of these lagoons require long‐term monitoring, including keystone taxa like the brine shrimp Artemia. How Chile will combine biodiversity agreements, treaties on wetlands and endangered birds conservation under the soaring lithium demand to support electromobility? Chile's government has granted new lithium extraction quotas to mining companies until 2030, which raises a concern and shows the difficulty to reconcile profit‐driven economic development with nature conservation. As these lagoons may be shrinking and their food web altered, a problem only noticed so far by the declining flamingos, there is an urgent need to consider them in the environmental impact assessment legislation.
Intraspecies nucleotide sequence variation is a key to understanding the evolutionary history of a species, such as the geographic distribution and population structure. To date, numerous ...phylogenetic and population genetics studies have been conducted based on the sequences of a gene or an intergenic region on the mitochondrial genome (mtDNA), such as cytochrome c oxidase subunits or the D-loop. To evaluate the credibility of the usage of such ‘classic’ markers, we compared the phylogenetic inferences based on the analyses of the partial and entire mtDNA sequences. Importantly, the phylogenetic reconstruction based on the short marker sequences did not necessarily reproduce the tree topologies based on the analyses of the entire mtDNA. In addition, analyses on the datasets of various organisms revealed that the analyses based on the classic markers yielded phylogenetic trees with poor confidence in all tested cases compared to the results based on full-length mtDNA. These results demonstrated that phylogenetic analyses based on complete mtDNA sequences yield more insightful results compared to those based on mitochondrial genes and segments. To ameliorate the shortcomings of the classic markers, we identified a segment of mtDNA that may be used as an ‘approximate marker’ to closely reproduce the phylogenetic inference obtained from the entire mtDNA in the case of mammalian species, which can be utilized to design amplicon-seq-based studies. Our study demonstrates the importance of the choice of mitochondrial markers for phylogenetic analyses and proposes a novel approach to choosing appropriate markers for mammalian mtDNA that reproduces the phylogenetic inferences obtained from full-length mtDNA.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Ecosystems of inland saline waters play a significant role in the biosphere and human life. Various articles of this Special Issue are devoted to a wide range of issues of their study and management. ...This introductory article gives a general overview of the types of inland waters on the planet, as well as the features of their ecosystems, reflected in 18 articles of this Special Issue. Attention is also paid to modern problems of conservation and integrated sustainable use of aquatic ecosystems in a changing climate and increasing anthropogenic pressure on water bodies.
The hypersaline lagoons located in evaporation basins or salars (salt flats) in the Atacama Desert are extreme environments harbouring a specialised biota able to survive harsh conditions for life. ...The knowledge of the parasitic biodiversity of these extreme habitats is still scarce despite their functional importance in regulating relevant non-economic services like habitats of waterbirds. The present study is the first report on the cestode infection of
Artemia franciscana
Kellogg in Salar de Atacama lagoons in northern Chile. A total of 23 parasite larvae were isolated and identified as belonging to five cestode taxa of the order Cyclophyllidea: two species of the family Hymenolepididae, i.e.
Flamingolepis
sp. 1 and
Flamingolepis
sp. 2 (adults parasitic in flamingos); two species of Dilepididae, i.e.
Fuhrmannolepis averini
(adults parasitic in phalaropes) and
Eurycestus avoceti
(adult parasitic in charadriforms birds); and one species of Progynotaeniidae, i.e.
Gynandrotaenia
(?)
stammeri
(adult parasitic in flamingos). The cysticercoids of each species are described and figured. The study represents the first geographical record of the genera
Eurycestus
,
Gynandrotaenia
and
Fuhrmannolepis
in South America and the first report of
Gynandrotaenia
and
Flamingolepis
in
A. franciscana
in its native range. This survey also contributes to the knowledge of cestodes of Phoenicopteriformes and Charadriiformes and their life cycles in the Neotropical Region. A review of cestodes recorded in brine shrimps of the genus
Artemia
in the world is provided. Further studies on cestode fauna of aquatic birds and their intermediate hosts in hypersaline habitats of the Neotropical Region are needed to understand their functional role in such extreme and unique ecosystems.
Epigenetic variation affects gene expression without altering the underlying DNA sequence of genes controlling ecologically relevant phenotypes through different mechanisms, one of which is long ...non-coding RNAs (lncRNAs). This study identified and evaluated the gene expression of lncRNAs in the gill and mantle tissues of
individuals from two ecologically different sites: Cochamó (41°S) and Yaldad (43°S), southern Chile, both impacted by climatic-related conditions and by mussel farming given their use as seedbeds. Sequences identified as lncRNAs exhibited tissue-specific differences, mapping to 3.54 % of the gill transcriptome and 1.96 % of the mantle transcriptome, representing an average of 2.76 % of the whole transcriptome. Using a high fold change value (≥|100|), we identified 43 and 47 differentially expressed lncRNAs (DE-lncRNAs) in the gill and mantle tissue of individuals sampled from Cochamó and 21 and 17 in the gill and mantle tissue of individuals sampled from Yaldad. Location-specific DE-lncRNAs were also detected in Cochamó (65) and Yaldad (94) samples. Via analysis of the differential expression of neighboring protein-coding genes, we identified enriched GO terms related to metabolic, genetic, and environmental information processing and immune system functions, reflecting how the impact of local ecological conditions may influence the
(epi)genome expression. These DE-lncRNAs represent complementary biomarkers to DNA sequence variation for maintaining adaptive differences and phenotypic plasticity to cope with natural and human-driven perturbations.
Harmful algal blooms (HABs) cause severe socioecological, economic, food innocuity, and public health problems in countries where aquaculture, fisheries, and tourism share marine ecosystem goods and ...services. HABs will likely intensify with rising eutrophication, ocean warming, acidification and climatic atmospheric and oceanographic oscillations (e.g., El Niño). During the Decade of Ocean Science for Sustainable Development (2021–2030), it is imperative to produce knowledge to predict HABs and mitigate their severe negative sustainability consequences. This review on coevolved symbiotic and antagonistic algae-bacteria interactions highlights the HAB holobiome, i.e., phycosphere-attached and free-living bacteria, as potential bioindicators of bloom onset and decline as they promote, inhibit or suppress algal growth. The reviewed literature led us to discuss (1) the conceptual issues and experimental approach required to generate and include the HAB holobiome data into monitoring schemes to evaluate the resulting predictive model, (2) the relevance of an integrated science-policy approach to articulate the holobiome knowledge among stakeholders, including policymakers, for the efficient use and adaptive management of ecosystem services, and 3) a way to translate, once validated, the holobiome-based predictive model into a widely adopted policy. In this sense, the ongoing Monitoring Algae in Chile project (MACH; www.mach-satreps.org/en/) provides a framework to articulate the holobiome science with policy to establish reliable forecast systems to minimize HAB impact on public health, aquaculture and fisheries activities. This Chilean-Japanese research collaboration builds on the lessons from the catastrophic HAB event on Chiloé Island (May 2016), where world-class salmon, mussel aquaculture, and artisanal fishers coexist.
•Harmful algal blooms (HABs) cause severe ecological, socioeconomic, public health and sustainability problems.•The HAB holobiome, symbiotic and antagonist bacteria attached to algae, is a potential bioindicator of bloom dynamics.•The HAB holobiome is potentially a novel, ecosystem-based and complementary tool for HAB monitoring and early warning.•A transdisciplinary approach, including non-scientific stakeholders, is proposed for HAB forecasting and management.
Phytoplankton blooms, including harmful algal blooms (HABs), have serious impacts on ecosystems, public health, and productivity activities. Rapid detection and monitoring of marine microalgae are ...important in predicting and managing HABs. We developed a toolkit, the Suitcase Lab, to detect harmful algae species in the field. We demonstrated the Suitcase Lab’s capabilities for sampling, filtration, DNA extraction, and loop-mediated isothermal amplification (LAMP) detection in cultured
Alexandrium catenella
cells as well as Chilean coastal waters from four sites: Repollal, Isla García, Puerto Montt, and Metri. A LAMP assay using the Suitcase Lab in the field confirmed microscopic observations of
A. catenella
in samples from Repollal and Isla García. The Suitcase Lab allowed the rapid detection of
A. catenella
, within 2 h from the time of sampling, even at a single cell per milliliter concentrations, demonstrating its usefulness for quick and qualitative on-site diagnosis of target toxic algae species. This method is applicable not only to detecting harmful algae but also to other field studies that seek a rapid molecular diagnostic test.
The study of adaptive population differences is relevant for evolutionary biology, as it evidences the power of selective local forces relative to gene flow in maintaining adaptive phenotypes and ...their underlying genetic determinants. However, human-mediated hybridization through habitat translocations, a common and recurrent aquaculture practice where hybrids could eventually replace local genotypes, risk populations’ ability to cope with perturbations. The endemic marine mussel
Mytilus chilensis
supports a booming farming industry in the inner sea of Chiloé Island, southern Chile, which entirely relies on artificially collected seeds from natural beds that are translocated to ecologically different fattening centers. A matter of concern is how farm-impacted seedbeds will potentially cope with environmental shifts and anthropogenic perturbations. This study provides the first
de novo
transcriptome of
M. chilensis
; assembled from tissue samples of mantles and gills of individuals collected in ecologically different farm-impacted seedbeds, Cochamó (41°S) and Yaldad (43°S). Both locations and tissue samples differentially expressed transcripts (DETs) in candidate adaptive genes controlling multiple fitness traits, involved with metabolism, genetic and environmental information processing, and cellular processes. From 189,743 consensus contigs assembled: 1,716 (Bonferroni p
value
≤ 0.05) were DETs detected in different tissues of samples from different locations, 210 of them (fold change ≥ | 100|) in the same tissue of samples from a different location, and 665 (fold change ≥ | 4|) regardless of the tissue in samples from a different location. Site-specific DETs in Cochamó (169) and Yaldad (150) in candidate genes controlling tolerance to temperature and salinity shifts, and biomineralization exhibit a high number of nucleotide genetic variants with regular occurrence (frequency > 99%). This novel
M. chilensis
transcriptome should help assessing and monitoring the impact of translocations in wild and farm-impacted mussel beds in Chiloé Island. At the same time, it would help designing effective managing practices for conservation, and translocation traceability.
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