RESUMEN
Coevolutionary antagonism generates relentless selection that can favour genetic exchange, including transfer of antibiotic synthesis and resistance genes among bacteria, and sexual recombination of disease resistance alleles in eukaryotes. We report an unusual link between biological conflict and DNA transfer in bdelloid rotifers, microscopic animals whose genomes show elevated levels of horizontal gene transfer from non-metazoan taxa. When rotifers were challenged with a fungal pathogen, horizontally acquired genes were over twice as likely to be upregulated as other genes - a stronger enrichment than observed for abiotic stressors. Among hundreds of upregulated genes, the most markedly overrepresented were clusters resembling bacterial polyketide and nonribosomal peptide synthetases that produce antibiotics. Upregulation of these clusters in a pathogen-resistant rotifer species was nearly ten times stronger than in a susceptible species. By acquiring, domesticating, and expressing non-metazoan biosynthetic pathways, bdelloids may have evolved to resist natural enemies using antimicrobial mechanisms absent from other animals.
Asunto(s)
Transferencia de Gen Horizontal , Rotíferos , Animales , Rotíferos/genética , Rotíferos/metabolismo , Vías Biosintéticas/genética , Péptido Sintasas/genética , Péptido Sintasas/metabolismo , Policétidos/metabolismo , Filogenia , Familia de MultigenesRESUMEN
Estrogen receptors (ERs) are thought to be the ancestor of all steroid receptors and are present in most lophotrochozoans studied to date, including molluscs, annelids, and rotifers. A number of studies have investigated the functional role of estrogen receptors in invertebrate species, although most are in molluscs, where the receptor is constitutively active. In vitro experiments provided evidence for ligand-activated estrogen receptors in annelids, raising important questions about the role of estrogen signalling in lophotrochozoan lineages. Here, we review the concordant and discordant evidence of estradiol receptor signalling in lophotrochozoans, with a focus on annelids and rotifers. We explore the de novo synthesis of estrogens, the evolution and expression of estrogen receptors, and physiological responses to activation of estrogen receptors in the lophotrochozoan phyla Annelida and Rotifera. Key data are missing to determine if de novo biosynthesis of estradiol in non-molluscan lophotrochozoans is likely. For example, an ortholog for the CYP11 gene is present, but confirmation of substrate conversion and measured tissue products is lacking. Orthologs CYP17 and CYP19 are lacking, yet intermediates or products (e.g. estradiol) in tissues have been measured. Estrogen receptors are present in multiple species, and for a limited number, in vitro data show agonist binding of estradiol and/or transcriptional activation. The expression patterns of the lophotrochozoan ERs suggest developmental, reproductive, and digestive roles but are highly species dependent. E2 exposures suggest that lophotrochozoan ERs may play a role in reproduction, but no strong dose-response relationship has been established. Therefore, we expect most lophotrochozoan species, outside of perhaps platyhelminths, to have an ER but their physiological role remains elusive. Mining genomes for orthologs gene families responsible for steroidogenesis, coupled with in vitro and in vivo studies of the steroid pathway are needed to better assess whether lophotrochozoans are capable of estradiol biosynthesis. One major challenge is that much of the data are divided across a diversity of species. We propose that the polychaetes Capitella teleta or Platyneris dumerilii, and rotifer Brachionus manjavacas may be strong species choices for studies of estrogen receptor signalling, because of available genomic data, established laboratory culture techniques, and gene knockout potential.
Asunto(s)
Transducción de Señal , Animales , Transducción de Señal/fisiología , Transducción de Señal/genética , Receptores de Estradiol/metabolismo , Receptores de Estradiol/genética , Anélidos/metabolismo , Anélidos/genética , Receptores de Estrógenos/metabolismo , Receptores de Estrógenos/genética , Rotíferos/metabolismo , Rotíferos/genética , Estradiol/metabolismoRESUMEN
Microplastics (MPs) and nanoplastics (NPs) are emerging pollutants in the ocean, but their transfer and toxicity along the food chains are unclear. In this study, a marine rotifer (Brachionus plicatilis)-marine medaka (Oryzias melastigma) food chain was constructed to evaluate the transfer of polystyrene MPs and NPs (70 nm, 500 nm, and 2 µm, 2000 µg/L) and toxicity of 70 nm PS-NPs (0, 20, 200, and 2000 µg/L) on marine medaka after long-term food chain exposure. The results showed that the amount of 70 nm NPs accumulated in marine medaka was 1.24 µg/mg, which was significantly higher than that of 500 nm NPs (0.87 µg/mg) and 2 µm MP (0.69 µg/mg). Long-term food chain exposure to NPs caused microflora dysbiosis, resulting in activation of toll-like receptor 4 (TLR4) pathway, which induced liver inflammation. Moreover, NPs food chain exposure increased liver and muscle tissue triglyceride and lactate content, but decreased the protein, sugar, and glycogen content. NPs food chain exposure impaired reproductive function and inhibited offspring early development, which might pose a threat to the sustainability of marine medaka population. Overall, the study revealed the transfer of MPs and NPs and the effects of NPs on marine medaka along the food chain.
Asunto(s)
Oryzias , Rotíferos , Contaminantes Químicos del Agua , Animales , Microplásticos , Plásticos/toxicidad , Oryzias/fisiología , Cadena Alimentaria , Contaminantes Químicos del Agua/análisis , Rotíferos/metabolismo , Poliestirenos/toxicidadRESUMEN
Organophosphorus flame retardants (OPFRs) are frequently detected in aquatic environments and can potentially amplify the food chain, posing a potential risk to organisms. Marine invertebrates have primitive nervous systems to regulate behavior, but how they respond to OPFRs that are potentially neurotoxic substances is unclear. This study assessed changes in the feeding behavior of rotifer Brachionus plicatilis exposed to alkyl OPFRs tributyl phosphate (TnBP) (0.376 nM, 3.76 and 22.53 µM) to elucidate the mechanism of behavioral toxicity. TnBP at 22.53 µM reduced the ingestion and filtration rates of rotifers for Chlorella vulgaris and Phaeocystis globosa in a 24-h test and altered rotifer-P. globosa population dynamics in 15-d coculture. Ciliary beat frequency was also reduced, and the expression of genes encoding the cilia axoneme was downregulated. TnBP could inhibit rotifer acetylcholinesterase activity by binding this protein and reduce the expression of the exocytotic membrane protein syntaxin-4, suggesting a disorder in nervous regulation of cilia beat. Moreover, TnBP induced abnormal shape and dysfunction of mitochondria, which caused insufficient energy required for ciliary movement. This study revealed diverse neurotoxicity mechanisms of TnBP, particularly as a potentially competing acetylcholinesterase ligand for aquatic invertebrates. Our research also provides a meaningful reference for OPFR-induced behavioral toxicity assessments.
Asunto(s)
Chlorella vulgaris , Retardadores de Llama , Rotíferos , Animales , Acetilcolinesterasa/metabolismo , Cilios/metabolismo , Chlorella vulgaris/metabolismo , Axonema/metabolismo , Rotíferos/metabolismo , Organofosfatos , Conducta Alimentaria , Compuestos OrganofosforadosRESUMEN
Rotifers have great potential in controlling the harmful algae Phaeocystis blooms that frequently occur in coastal waters. To evaluate the effects of harmful algae on the key life-history traits of rotifer in eliminating Phaeocystis and reveal the underlying mechanism of these effects, we fed Brachionus plicatilis with Chlorella vulgaris and Phaeocystis globosa respectively, recorded the key life-history traits, and conducted transcriptomic analysis. Results showed that the rotifers feeding on P. globosa significantly decreased total offspring but obviously prolonged lifespan compared to those feeding on C. vulgaris, indicating that there was a trade-off between the reproduction and lifespan of rotifers feeding on algae with different nutrient contents. Nevertheless, rotifers can completely eliminate the population of P. globosa. The changes in the reproduction and lifespan of rotifers are highly correlated with algal key nutrition and the expression of some related genes. Transcriptomic analysis showed that the changes in the key life history traits of rotifers feeding on harmful algae are determined by regulating the expression of some key genes involved in the pathways of carbohydrate digestion and absorption, glycolysis, gluconeogenesis, unsaturated fatty acid biosynthesis, and environmental stress. Understanding the trade-off of the key life history traits of zooplankton in eliminating harmful algae from the underlying mechanism helps improve their application for controlling harmful algae.
Asunto(s)
Chlorella vulgaris , Haptophyta , Rasgos de la Historia de Vida , Rotíferos , Animales , Haptophyta/genética , Transcriptoma , Rotíferos/genética , Rotíferos/metabolismoRESUMEN
There are numerous surprising discoveries in current comprehensive biopolymer research, including the description of new types of biopolymers and the extension of their applications. The discovery of a new rotifer-specific biopolymer family (Rotimers) and the exceptional ability of these micrometazoans to inactivate and catabolize human-type neurotoxic aggregates (e.g., beta-amyloids, alpha-synucleins, prions) by their exudates can be mentioned as the original work of our research group. Rotimers are exogenous and protein complex molecules with a calcium-dependent production mechanism in both bdelloid and monogonant rotifers. However, their experimental and application possibilities are still unknown; only part of the class has been explored and described. Current Rotimer-related studies present promising biodiversity and bioactivity of these biomaterials (e.g., antiand disaggregation effects or high degrees of adhesion to other molecules). The primary objective of current research is to explore and develop their application in translational biomedicine. A key area is the design of drug candidates against neurodegeneration-related aggregates based on the molecular information provided by the composition, structure and function of Rotimers. These novel biomaterials have the potential to open new perspectives in the pharmaceutical industry and healthcare.
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Priones , Rotíferos , Animales , Materiales Biocompatibles , Biopolímeros/metabolismo , Biopolímeros/farmacología , Calcio/metabolismo , Humanos , Priones/metabolismo , Priones/farmacología , Rotíferos/metabolismo , Sinucleínas/metabolismoRESUMEN
Glyphosate levels and the transfer of glyphosate across trophic levels have rarely been studied in zooplankton. The food preferences of zebrafish during the first-feeding stage (which is critical for the survival of organisms), were analyzed because of the requirement for live food. Larval survival begins to be affected when glyphosate intake exceeds 0.3666 µg/larvae/day, in the case that only the food is contaminated; if the medium is also contaminated, the effects on survival start from 0.2456 µg/larvae/day. It was shown that glyphosate was more likely to be incorporated through the medium than through the food (zooplankton), which supports the results of previous studies that have ruled out the potential for biomagnification. The bioconcentration factor (BCF) of glyphosate was determined using an ELISA tests specific to measure glyphosate in the fish D. rerio, the rotifers Brachionus calyciflorus and Lecane papuana, and the cladoceran Ceriodaphnia dubia. The experimental design consisted in exposing seven zebrafish adults per replica (four replicates) in three treatments 1, 5, and 10 mg/L of glyphosate for 96 h to obtain bioconcentration factors in the gills, liver, and muscle. These concentrations were selected as potential glyphosate concentrations right after application as double highest reported concentration. Glyphosate levels in zooplankton can represent up to 6.26% of the total weight of rotifers (BFC = 60.35) and in zebrafish adult organs were less than 8 µg/mg of tissue (BCF values < 6). Although glyphosate does not biomagnify, our results suggest that glyphosate affected the dynamics between zooplankton and zebrafish larvae, diminishing survival and feeding rates, given that zooplankton species bioconcentrate glyphosate in large quantities. The BCF values found in this contribution are higher than expected. Glyphosate exposure affected energy metabolism and feeding behavior of zebrafish larvae, which presented high mortality rates at environmentally relevant concentrations.
Asunto(s)
Rotíferos , Contaminantes Químicos del Agua , Animales , Pez Cebra/fisiología , Glicina/toxicidad , Rotíferos/metabolismo , Larva/metabolismo , Zooplancton/metabolismo , Conducta Alimentaria , Contaminantes Químicos del Agua/toxicidad , Contaminantes Químicos del Agua/metabolismo , GlifosatoRESUMEN
Due to their high biodiversity and adaptation to a mutable and challenging environment, aquatic lophotrochozoan animals are regarded as a virtually unlimited source of bioactive molecules. Among these, lectins, i.e., proteins with remarkable carbohydrate-recognition properties involved in immunity, reproduction, self/nonself recognition and several other biological processes, are particularly attractive targets for biotechnological research. To date, lectin research in the Lophotrochozoa has been restricted to the most widespread phyla, which are the usual targets of comparative immunology studies, such as Mollusca and Annelida. Here we provide the first overview of the repertoire of the secretory lectin-like molecules encoded by the genomes of six target rotifer species: Brachionus calyciflorus, Brachionus plicatilis, Proales similis (class Monogononta), Adineta ricciae, Didymodactylos carnosus and Rotaria sordida (class Bdelloidea). Overall, while rotifer secretory lectins display a high molecular diversity and belong to nine different structural classes, their total number is significantly lower than for other groups of lophotrochozoans, with no evidence of lineage-specific expansion events. Considering the high evolutionary divergence between rotifers and the other major sister phyla, their widespread distribution in aquatic environments and the ease of their collection and rearing in laboratory conditions, these organisms may represent interesting targets for glycobiological studies, which may allow the identification of novel carbohydrate-binding proteins with peculiar biological properties.
Asunto(s)
Organismos Acuáticos , Lectinas/metabolismo , Rotíferos/metabolismo , Animales , Genoma de los HelmintosRESUMEN
The Rotimer, a rotifer-specific biopolymer, is an exogenic bioactive exudate secreted by different monogonant species (e.g. Euchlanis dilatata or Lecane bulla). The production of this viscoelastic biomolecule is induced by different micro-particles, thereby forming a special Rotimer-Inductor Conglomerate (RIC) in a web format. In this case, the water insoluble Carmine crystals, filtered to size (max. diameter was 50 µm), functioned as an inductor. The RIC production is an adequate empirical indicator to follow up this filamentous biopolymer secretion experientially; moreover, this procedure is very sensitive to the environmental factors (temperature, pH, metals and possible natural pollutant agents). The above mentioned species show completely different reactions to these factors, except to the presence of calcium and to the modulating effects of different drugs. One of the novelties of this work is that the Rotimer secretion and consequently, the RIC-formation is a mutually obligatory and evolutionary calcium-dependent process in the concerned monogonants. This in vivo procedure needs calcium, both for the physiology of animals and for fiber formation, particularly in the latter case. The conglomerate covered area (%) and the detection of the longest filament (mm) of the given RIC were the generally and simultaneously applied methods in the current modulating experiments. Exploring the regulatory (e.g. calcium-dependency) and stimulating (e.g. Lucidril effect) possibilities of biopolymer secretion are the basis for optimizing the RIC-production capacities of these micro-metazoans.
Asunto(s)
Biopolímeros/biosíntesis , Calcio/farmacología , Ambiente , Contaminantes Ambientales/farmacología , Exudados y Transudados , Rotíferos/metabolismo , Animales , Concentración de Iones de Hidrógeno , Rotíferos/efectos de los fármacos , TemperaturaRESUMEN
Besides the adverse biological effects induced by microplastics (MPs), the effects associated with sorption of ambient pollutants on MPs are considered as an emerging environmental problem as MPs act as a mediator of pollutants. The present study examines the combined effects of nano(micro)plastics (NMPs) and arsenic (As) by exposing the marine rotifer Brachionus plicatilis to MP particles at the micro-scale (6 µm) and nano-scale (nanoplastics, NPs) (50 nm) along with As. In vivo toxicity, bioaccumulation, and biochemical reactions were used to examine the effects of combined exposure. The results of in vivo experiments showed that As toxicity increased with NP exposure, whereas toxicity was alleviated by MPs, indicating a different mode of action between NPs and MPs in combination with As. The highest level of As bioaccumulation was detected in NP + As groups, and followed by MP + As and As-only exposure groups, whereas no significant difference between groups was shown for As metabolites. In addition, the activity of several ATP-binding cassette proteins that confer multixenobiotic resistance, which is responsible for efflux of As, was activated by As but significantly inhibited by NP exposure, supporting the findings of in vivo experiments. Our results show that the effects of combining exposure to As with NP and MPs differ depending on particle size and provide an in-depth understanding of both environmental pollutants.
Asunto(s)
Arsénico/toxicidad , Microplásticos/toxicidad , Nanopartículas/toxicidad , Rotíferos/efectos de los fármacos , Contaminantes Químicos del Agua/toxicidad , Transportadoras de Casetes de Unión a ATP/metabolismo , Animales , Arsénico/metabolismo , Bioacumulación , Disponibilidad Biológica , Microplásticos/metabolismo , Modelos Teóricos , Nanopartículas/metabolismo , Rotíferos/metabolismo , Natación , Contaminantes Químicos del Agua/metabolismoRESUMEN
The baking industries and disinfection of tap water released a considerable amount of bromate into surface water, which has been reported as a carcinogenic compound to mammals. Rotifers play an important role in freshwater ecosystems and are model organisms to assess environmental contamination. In the present study, the effects of different concentrations (0.001, 0.01, 0.1, 1, 10, 100 and 200 mg/L) of bromate on the life-table and population growth parameters were investigated in the rotifer Brachionus calyciflorus. The results showed that the 24-h LC50 of bromate to B. calyciflorus was 365.29 mg/L (95%Cl: 290.37-480.24). Treatments with 0.01, 10 and 200 mg/L bromate shorten the reproductive period. High levels of bromate (100 and 200 mg/L) significantly decreased net reproductive rate, intrinsic rate of population increase, life span, mictic rate of B. calyciflorus. To investigate the underlying mechanisms, swimming speed and antioxidative biomarkers were compared between bromate treatments and the control. The results showed that glutathione (GSH) and malondialdehyde (MDA) contents, total superoxide dismutase (T-SOD) and peroxidase (POD) activities decreased significantly in response to bromate exposure and the reasons required further investigation. Treatments with 0.001-200 mg/L bromate all significantly reduced swimming linear speed to rotifer larvae and treatments with 100-200 mg/L bromate significantly suppressed the swimming linear speed of adult rotifer. These changes would reduce filtration of algal food and could explain the decreased survival and reproduction. Overall, bromate may not show acute toxicity to rotifers, but still have potential adverse effects on rotifer behavior, which may then influence the community structure in aquatic ecosystems.
Asunto(s)
Bromatos/toxicidad , Rotíferos/efectos de los fármacos , Rotíferos/fisiología , Contaminantes Químicos del Agua/toxicidad , Animales , Antioxidantes/metabolismo , Biomarcadores/metabolismo , Bromatos/análisis , Larva/efectos de los fármacos , Larva/fisiología , Crecimiento Demográfico , Reproducción/efectos de los fármacos , Rotíferos/crecimiento & desarrollo , Rotíferos/metabolismo , Natación , Contaminantes Químicos del Agua/análisisRESUMEN
The chemical ecology of rotifers has been little studied. A yet unknown property is presented within some monogonant rotifers, namely the ability to produce an exogenic filamentous biopolymer, named 'Rotimer'. This rotifer-specific viscoelastic fiber was observed in six different freshwater monogonants (Euchlanis dilatata, Lecane bulla, Lepadella patella, Itura aurita, Colurella adriatica and Trichocerca iernis) in exception of four species. Induction of Rotimer secretion can only be achieved by mechanically irritating rotifer ciliate with administering different types (yeast cell skeleton, denatured BSA, epoxy, Carmine or urea crystals and micro-cellulose) and sizes (approx. from 2.5 to 50 µm diameter) of inert particles, as inductors or visualization by adhering particles. The thickness of this Rotimer is 33 ± 3 nm, detected by scanning electron microscope. This material has two structural formations (fiber or gluelike) in nano dimension. The existence of the novel adherent natural product becomes visible by forming a 'Rotimer-Inductor Conglomerate' (RIC) web structure within a few minutes. The RIC-producing capacity of animals, depends on viability, is significantly modified according to physiological- (depletion), drug- (toxin or stimulator) and environmental (temperature, salt content and pH) effects. The E. dilatata-produced RIC is affected by protein disruptors but is resistant to several chemical influences and its Rotimer component has an overwhelming cell (algae, yeast and human neuroblastoma) motility inhibitory effect, associated with low toxicity. This biopolymer-secretion-capacity is protective of rotifers against human-type beta-amyloid aggregates.
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Biopolímeros/metabolismo , Rotíferos/metabolismo , Péptidos beta-Amiloides/farmacología , Animales , Biopolímeros/química , Biopolímeros/farmacología , Línea Celular Tumoral , Movimiento Celular/efectos de los fármacos , Agua Dulce/microbiología , Humanos , Rotíferos/clasificación , Rotíferos/efectos de los fármacos , TemperaturaRESUMEN
Diurnal temperature fluctuations affect ectothermic species more than endothermic taxa. We tested the effect of three fixed temperatures (20, 25 and 30 °C) and a 24 h variable (20-30 °C) on the population growth and fatty acid profiles of the common rotifer Brachionus calyciflorus. Depending on the temperature treatment, the peak population abundances of B. calyciflorus varied from 65 to 80 ind./ml, the lowest being on variable temperature range. The rate of population increase varied from 0.31 to 0.52 per day, highest being at 30 °C. There was a curvilinear relationship between the population density and the egg ratio (number of eggs/female) in all the tested temperature regimes. The egg ratio was higher (>0.6) for treatments involving fixed temperatures, but for variable temperature regime, the egg ratios were lower (<0.5). Temperature also induced changes in the fatty acid content of B. calyciflorus. While the total saturated fatty acids increased, both mono-unsaturated and poly-unsaturated fatty acids decreased with increasing temperature regime. These results have been interpreted in relation to the role of temperature (both intensity and mode of exposure) on the population growth characteristics of rotifers.
Asunto(s)
Ácidos Grasos/metabolismo , Rotíferos/metabolismo , Temperatura , Animales , Femenino , Óvulo , Densidad de PoblaciónRESUMEN
In unpredictable environments in which reliable cues for predicting environmental variation are lacking, a diversifying bet-hedging strategy for diapause exit is expected to evolve, whereby only a portion of diapausing forms will resume development at the first occurrence of suitable conditions. This study focused on diapause termination in the rotifer Brachionus plicatilis s.s., addressing the transcriptional profile of diapausing eggs from environments differing in the level of predictability and the relationship of such profiles with hatching patterns. RNA-Seq analyses revealed significant differences in gene expression between diapausing eggs produced in the laboratory under combinations of two contrasting selective regimes of environmental fluctuation (predictable vs unpredictable) and two different diapause conditions (passing or not passing through forced diapause). The results showed that the selective regime was more important than the diapause condition in driving differences in the transcriptome profile. Most of the differentially expressed genes were upregulated in the predictable regime and mostly associated with molecular functions involved in embryo morphological development and hatching readiness. This was in concordance with observations of earlier, higher, and more synchronous hatching in diapausing eggs produced under the predictable regime.
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Diapausa/fisiología , Rotíferos/metabolismo , Rotíferos/fisiología , Análisis de Secuencia de ARN/métodos , Animales , Reproducción/fisiologíaRESUMEN
The DNA repair system has evolved from the common ancestor of all life forms and its function is highly conserved within eukaryotes. In this study, to reveal the role of DNA double-strand break repair (DSB) genes in response to benzo[α]pyrene (B[α]P), we first identified DSB genes in relation to homologous recombination and non-homologous end joining events in four Brachionus rotifer spp.: B. calyciflorus, B. koreanus, B. plicatilis, and B. rotundiformis. In all the Brachionus spp., 39 orthologous genes to human DSB repair genes were identified. Furthermore, three genes in B. koreanus, two genes in B. plicatilis, and one gene in B. calyciflorus and B. rotundiformis were present as duplicated genes, indicating that these genes were diversified over speciation in the genus Brachionus. Moreover, we compared DSB repair genes on the gene structures in four monogonont Brachionus rotifers and the bdelloid rotifer Adineta vaga, which possesses highly efficient DNA repair ability. The transcriptional responses of four monogonont Brachionus rotifers in response to B[α]P exposure showed how B[α]P exposure led to DSBs and subsequently recruited DNA DSB repair pathways in the rotifer B. koreanus. Taken together, this study provides a better understanding of the potential role of DSB repair genes in the monogonont rotifer Brachionus spp. in response to B[α]P.
Asunto(s)
Benzo(a)pireno/toxicidad , Rotíferos/metabolismo , Contaminantes Químicos del Agua/toxicidad , Animales , Benzo(a)pireno/metabolismo , ADN/metabolismo , Roturas del ADN de Doble Cadena , Genoma , HumanosRESUMEN
Low-temperature exposure prolongs lifespans and changes lipid metabolism but the relationship between longevity and lipids is largely unknown. Here, we examine the relationship between longevity and lipid metabolism at low temperatures (20⯰C and 15⯰C) compared with a 25⯰C control. Life parameters, fatty acid composition, and transcriptome changes were analyzed in the monogonont rotifer Brachionus koreanus. In vivo life-parameter data indicate that lifespan and fecundity exhibit opposite correlations at low temperatures. The amount of total fatty acids decreased significantly at low temperatures but areas stained with Nile red increased at 15⯰C compared with the control. From RNA-seq-based transcriptional analysis, gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway-enrichment analysis were conducted. GO analysis shows that telomeres were positively regulated at low temperatures. KEGG pathway-enrichment results indicate that gene expression involved in lipid metabolism was activated with increased glycerol and/or choline synthesis at low temperatures. We suggest that reduced reproductive rates are associated with a decrease of lecithin, which is involved in the conversion of glycerol to triacylglycerol in response to low temperatures by lowering the temperature of body fluid.
Asunto(s)
Frío , Metabolismo de los Lípidos , Rotíferos/metabolismo , Animales , Colina/biosíntesis , Ácidos Grasos/metabolismo , Glicerol/metabolismo , Longevidad , Rotíferos/genética , Telómero , TranscriptomaRESUMEN
Salinity stress influences energy balance, induction of stress proteins, and reproductive success, which are important to life parameters of aquatic organisms. However, physiological and molecular responses of salinity stress have not been studied in the rotifer. To understand the effects of salinity changes on the rotifer, we examined the marine monogonont rotifer Brachionus plicatilis (B. plicatilis) for salinity stress-induced changes in population growth, reactive oxygen species (ROS) levels, and antioxidant enzymatic activities (e.g., glutathione S-transferase [GST], superoxide dismutase [SOD] and catalase [CAT]). In addition, antioxidant-related transcripts (GSTs [GSTs-1-1 and GSTs-1-2], MnSOD1 and CAT2) were investigated in different salinity-exposed rotifers. A significant decrease (P < 0.05) in population growth was observed in response to high salinity (35 psu) in B. plicatilis. Moreover, the rotifers exposed to high salinity (35 psu) exhibited increased ROS levels with enhanced SOD and CAT enzymatic activities, compared to those in controls (15 psu). Additionally, significant change (P < 0.05) of antioxidant-related genes (GSTs [GSTs-1-1 and GSTs-1-2], MnSOD1 and CAT2) was observed in response to different salinities. Overall, these findings indicate that high salinity induce ROS-mediated oxidative stress, leading to growth retardation and modulation of the antioxidant defense system in B. plicatilis. These findings provide a better understanding on the adverse effects of salinity changes on lifecycle parameters and oxidative stress defense mechanism in rotifers.
Asunto(s)
Antioxidantes/metabolismo , Estrés Oxidativo , Rotíferos/metabolismo , Salinidad , Animales , Dinámica Poblacional , Rotíferos/genéticaRESUMEN
Harmful Phaeocystis blooms disrupt seawater recreation and pose serious challenges to aquatic animals. The growth performance, phenotypic traits, and antioxidant responses of Brachionus plicatilis Müller to different proportions of Phaeocystis globosa were evaluated. B. plicatilis rotifers were exposed to cultures with Chlorella sp. and P. globosa alone and in mixtures of these two algae with proportions of 25%, 50%, and 75%. The total proportions of the two algae were maintained at 100%. Results showed that P. globosa inhibited the rotifer net reproduction rate, intrinsic growth rate, and finite rate of increase (P < 0.01). It induced the formation of defense phenotypic traits in terms of the increased posterolateral spine length and the reduced body length, swimming speed, and grazing rate of B. plicatilis (P < 0.001). Superoxide dismutase and catalase activities decreased, but the reactive oxygen species levels increased as the proportions of P. globosa increased (P < 0.01). The mixture of 50% Chlorella and 50% Phaeocystis positively affected the glutathione content, glutathione peroxidase activity, and generation time of rotifers (P < 0.01). Although P. globosa released toxicants with harmful effects on the growth performance of B. plicatilis, rotifers changed their antioxidant defense system and formed defense phenotypic traits in response to eutrophic conditions.
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Antioxidantes/metabolismo , Haptophyta/crecimiento & desarrollo , Floraciones de Algas Nocivas , Rotíferos/crecimiento & desarrollo , Animales , Chlorella/crecimiento & desarrollo , Glutatión/metabolismo , Fenotipo , Especies Reactivas de Oxígeno/metabolismo , Rotíferos/metabolismo , Rotíferos/fisiología , Agua de Mar/química , NataciónRESUMEN
Biochemical food quality constraints affect the performance of consumers and mediate trait variation among and within consumer species. To assess inter- and intraspecific differences in fatty acid retention and conversion in freshwater rotifers, we provided four strains of two closely related rotifer species, Brachionus calyciflorus sensu stricto and Brachionus fernandoi, with food algae differing in their fatty acid composition. The rotifers grazed for 5 days on either Nannochloropsis limnetica or Monoraphidium minutum, two food algae with distinct polyunsaturated fatty acid (PUFA) profiles, before the diets were switched to PUFA-free Synechococcus elongatus, which was provided for three more days. We found between- and within-species differences in rotifer fatty acid compositions on the respective food sources and, in particular, highly specific acclimation reactions to the PUFA-free diet. The different reactions indicate inter- but also intraspecific differences in physiological traits, such as PUFA retention, allocation and bioconversion capacities, within the genus Brachionus that are most likely accompanied by differences in their nutritional demands. Our data suggest that biochemical food quality constraints act differently on traits of closely related species and of strains of a particular species and thus might be involved in shaping ecological interactions and evolutionary processes. This article is part of the theme issue 'The next horizons for lipids as 'trophic biomarkers': evidence and significance of consumer modification of dietary fatty acids'.
Asunto(s)
Aclimatación , Alimentación Animal/análisis , Ácidos Grasos/metabolismo , Rotíferos/metabolismo , Animales , Chlorophyta/química , Dieta/veterinaria , Calidad de los Alimentos , Especificidad de la Especie , Estramenopilos/química , Synechococcus/químicaRESUMEN
Gluatathione S-transferases (GSTs) play a major role in phase II detoxification pathway to defend organisms in response to oxidative stress induced by xenobiotics and toxicants. To reveal the role of the recombinant GST zeta protein from the freshwater rotifer Brachionus calyciflorus, we isolated the zeta class GST in the freshwater rotifer B. calyciflorus. The recombinant B. calyciflorus GST zeta protein was highly expressed in the transformed Escherichia coli using pET28a vector. To determine its characteristics, effects of pH and temperature on B. calyciflorus GST zeta with enzymatic kinetics were also studied. In addition, a disk diffusion assay, uncovering the ability of transformed GST zeta in Escherichia coli, revealed that E. coli-transformed GST zeta significantly protected the transformed E. coli cells in response to oxidative stress induced by H2O2 and metals such as mercury and cadmium. These results suggest that B. calyciflorus GST zeta recombinant protein is likely playing an important role to defend in response to metal-induced oxidative stress, providing a better understanding on the possible antioxidant role of GST zeta class in B. calyciflorus.