Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 14 de 14
Filter
Add more filters










Publication year range
1.
J Therm Biol ; 99: 102997, 2021 Jul.
Article in English | MEDLINE | ID: mdl-34420629

ABSTRACT

Large branchiopods are specialist crustaceans adapted for life in temporary, thermally dynamic wetland ecosystems. Certain large branchiopod species are, however, restricted to specific temporary wetland types, exemplified by their physico-chemical and hydroperiod characteristics. Here, we contrasted the thermal preference and critical thermal maxima (CTmax) and minima (CTmin) of southern African anostracans and spinicaudatans found exclusively in either temporary rock-pool or pan wetland types. We hypothesized that environment of origin would be a good predictor of thermal preference and critical thermal limits. To test this, Branchiopodopsis tridens (Anostraca) and Leptestheria brevirostris (Spinicaudata) were collected from rock-pool habitats, while Streptocephalus cafer (Anostraca) and a Gondwanalimnadia sp. (Spinicaudata) were collected from pan habitats. In contrast to our hypothesis, taxonomic relatedness was a better predictor of CTmax and temperature preference than environment of origin. Spinicaudatans were significantly more tolerant of high temperatures than anostracans, with L. brevirostris and Gondwanalimnadia sp. median CTmax values of 45.1 °C and 44.1 °C, respectively, followed by S. cafer (42.8 °C) and B. tridens (41.4 °C). Neither environment or taxonomic relatedness were good predictors of CTmin trends, with B. tridens (0.9 °C) and Gondwanalimnadia sp. (2.1 °C) having the lowest median CTmin values, followed by L. brevirostris (3.4 °C) and S. cafer (3.6 °C). On the contrary, temperature preferences differed according to taxa, with spinicaudatans significantly preferring higher temperatures than anostracans. Leptestheria brevirostris and Gondwanalimnadia sp. both spent most time at temperatures 30-32 °C, S. cafer at 18-20 °C and B. tridens at 21-23 °C. Constrained thermal traits reported here suggest that the studied anostracans might be more susceptible to projected climatic warming than the spinicaudatans, irrespective of habitat type, however, these taxa may also compensate through phenotypic plasticity.


Subject(s)
Crustacea/physiology , Thermotolerance , Wetlands , Animals , Anostraca/physiology , Temperature
2.
Front Immunol ; 11: 1511, 2020.
Article in English | MEDLINE | ID: mdl-32765521

ABSTRACT

The symbiotic shrimp Rimicaris exoculata dominates the macrofauna inhabiting the active smokers of the deep-sea mid Atlantic ridge vent fields. We investigated the nature of the host mechanisms controlling the vital and highly specialized ectosymbiotic community confined into its cephalothoracic cavity. R. exoculata belongs to the Pleocyemata, crustacean brooding eggs, usually producing Type I crustins. Unexpectedly, a novel anti-Gram-positive type II crustin was molecularly identified in R. exoculata. Re-crustin is mainly produced by the appendages and the inner surfaces of the cephalothoracic cavity, embedding target epibionts. Symbiosis acquisition and regulating mechanisms are still poorly understood. Yet, symbiotic communities were identified at different steps of the life cycle such as brooding stage, juvenile recruitment and molt cycle, all of which may be crucial for symbiotic acquisition and control. Here, we show a spatio-temporal correlation between the production of Re-crustin and the main ectosymbiosis-related life-cycle events. Overall, our results highlight (i) a novel and unusual AMP sequence from an extremophile organism and (ii) the potential role of AMPs in the establishment of vital ectosymbiosis along the life cycle of deep-sea invertebrates.


Subject(s)
Anostraca/physiology , Antimicrobial Cationic Peptides/metabolism , Antimicrobial Cationic Peptides/pharmacokinetics , Arthropod Proteins/metabolism , Gram-Positive Bacteria/physiology , Gram-Positive Bacterial Infections/immunology , Pore Forming Cytotoxic Proteins/metabolism , Animals , Antimicrobial Cationic Peptides/genetics , Ecosystem , Host-Pathogen Interactions , Life Cycle Stages , Oceans and Seas , Pore Forming Cytotoxic Proteins/genetics , Symbiosis
3.
BMC Ecol ; 18(1): 2, 2018 01 24.
Article in English | MEDLINE | ID: mdl-29361977

ABSTRACT

BACKGROUND: Higher temperatures and increased environmental variability under climate change could jeopardize the persistence of species. Organisms that rely on short windows of rainfall to complete their life-cycles, like desert annual plants or temporary pool animals, may be particularly at risk. Although some could tolerate environmental changes by building-up banks of propagules (seeds or eggs) that buffer against catastrophes, climate change will threaten this resilience mechanism if higher temperatures reduce propagule survival. Using a crustacean model species from temporary waters, we quantified experimentally the survival and dormancy of propagules under anticipated climate change and used these demographic parameters to simulate long term population dynamics. RESULTS: By exposing propagules to present-day and projected daily temperature cycles in an 8 month laboratory experiment, we showed how increased temperatures reduce survival rates in the propagule bank. Integrating these reduced survival rates into population models demonstrated the inability of the bank to maintain populations; thereby exacerbating extinction risk caused by shortened growing seasons. CONCLUSIONS: Overall, our study demonstrates that climate change could threaten the persistence of populations by both reducing habitat suitability and eroding life-history strategies that support demographic resilience.


Subject(s)
Anostraca/physiology , Climate Change , Ecosystem , Fresh Water , Life History Traits , Zooplankton/physiology , Animals , Models, Biological , Population Dynamics , Seasons , Temperature
4.
PLoS One ; 12(6): e0179449, 2017.
Article in English | MEDLINE | ID: mdl-28654929

ABSTRACT

Temperature effects on organisms are of multiple scientific interests, such as for their life history performance and for the study of evolutionary strategies. We have cultured two sympatric branchiopod species from an ephemeral pond in northern Taiwan, Branchinella kugenumaensis and Eulimnadia braueriana, and compared their hatching rate, maturation time, sex ratio, growth of body length, survivorship, clutch size, net reproductive rate R0, generation time TG, and intrinsic rate of natural increase r in relation to temperature (15, 20, 25 and 30°C). We found that E. braueriana had a significantly higher temperature-dependent fecundity and intrinsic population growth pattern (R0 and r). In contrast, B. kugenumaensis reproduced much slower than E. braueriana with much lower R0 (90-100 folds less) and r (about 10 folds less) at 15, 20 and 25°C and with a double as long TG at 20 and 25°C. In addition, E. braueriana increased its chance of hermaphroditic sexual reproductive mode at higher temperature because of a significantly delayed maturation of males from hermaphrodites. In contrast, B. kugenumaensis showed no significant change in reproductive mode with temperature. This is the first study indicating a significant differentiation in life history parameters of two sympatric branchiopods mediated by temperature.


Subject(s)
Crustacea/physiology , Life History Traits , Reproduction/physiology , Sympatry/physiology , Temperature , Animals , Anostraca/physiology , Fertility/physiology , Wetlands
5.
Sci Rep ; 6: 29451, 2016 07 11.
Article in English | MEDLINE | ID: mdl-27404276

ABSTRACT

Temporary pool inhabitants face altered inundation regimes under climate change. While their exposure to these changes has received considerable attention, few studies have investigated their sensitivity or adaptability. Here, we use zooplankton as a model to explore how decreasing hydroperiods affect extinction risks and assess whether changes in life history traits could promote persistence. For this, we construct a three-stage matrix population model parameterised with realistic life-history values for the fairy shrimp Branchipodopsis wolfi from pools with varying hydroperiods. Our results suggest that extinction risks increase drastically once the median hydroperiod drops below a critical threshold. Although changes in life-history parameters could potentially compensate for this risk, the relative importance of each trait for population growth depends on the median hydroperiod. For example, survival of dormant eggs seemed to be most important when hydroperiods were short while the survival of freshly laid eggs and adult individuals were more important in longer-lived pools. Overall, this study demonstrates that zooplankton species are sensitive to climate change and that the adaptive capacity of organisms from temporary pools with dissimilar hydrology hinges on selection of different life history traits.


Subject(s)
Anostraca/physiology , Climate Change , Ecological Parameter Monitoring/methods , Life History Traits , Zooplankton/physiology , Animals , Ecosystem , Extinction, Biological , Ovum/physiology
6.
J Therm Biol ; 53: 46-52, 2015 Oct.
Article in English | MEDLINE | ID: mdl-26590455

ABSTRACT

Small water bodies in cold climate respond fast to global warming, and species adapted to such habitats may be valuable indicators for climate change. We investigated the geographical and physiological temperature limits of the Arctic fairy shrimp (Branchinecta paludosa), which is common in cold water arctic ponds, but at present retracts its range in alpine areas along its southern outreach of Norway. Seasonal logging of water temperatures along an altitudinal transect revealed an upper temperature limit of 12.7°C for its presence, which closely matched a calculated upper temperature limit of 12.9°C throughout its entire Norwegian range. Field data hence point to cold stenotherm features, which would be consistent with its Arctic, circumpolar distribution. Lab experiments, on the other hand, revealed a linear increase in respiration over 10-20°C. When fed ad libitum somatic growth increased with temperature, as well, without negative physiological impacts of higher temperatures. The absence of Branchinecta paludosa in ponds warmer than 13°C could still be due to a mismatch between temperature dependent metabolism and limited energy supply in these ultraoligotrophic water bodies. We discuss the concept of cold stenothermy in this context, and the impacts of regional warming on the future distribution of the Arctic fairy shrimp.


Subject(s)
Acclimatization , Cold Temperature , Ecosystem , Animals , Anostraca/physiology , Biomass , Seasons
7.
Integr Comp Biol ; 52(1): 53-63, 2012 Jul.
Article in English | MEDLINE | ID: mdl-22596058

ABSTRACT

Animals often facultatively engage in less risky behavior when predators are present. Few studies, however, have investigated whether, or how, such predator-mediated behavior promotes diversification. Here, we ask whether tadpoles of the spadefoot toad Scaphiopus couchii have a diminished ability to utilize a potentially valuable resource--anostracan fairy shrimp--because of behavioral responses to predation risk imposed by carnivorous tadpoles of the genus Spea. Observations of a congener of Sc. couchii that occurs in allopatry with Spea, coupled with an ancestral character state reconstruction, revealed that Sc. couchii's ancestors likely consumed shrimp. By experimentally manipulating the presence of Spea carnivore-morph tadpoles in microcosms, we found that Sc. couchii reduce feeding and avoid areas where both Spea carnivores and shrimp occur. We hypothesize that the recurrent expression of such behaviors in sympatric populations of Sc. couchii led to the evolutionary fixation of a detritivorous feeding strategy, which is associated with a reduced risk of predation from Spea carnivores. Generally, predator-mediated behavior might play a key role in promoting diversification of feeding strategies.


Subject(s)
Genetic Speciation , Larva/physiology , Predatory Behavior/physiology , Selection, Genetic , Adaptation, Physiological , Animals , Anostraca/physiology , Anura , Diet , Escape Reaction , Female , Male , Ponds , Population Dynamics , Regression Analysis , Species Specificity , Sympatry
8.
Arthropod Struct Dev ; 41(3): 271-9, 2012 May.
Article in English | MEDLINE | ID: mdl-22445350

ABSTRACT

Eubranchipus grubii (Crustacea, Branchiopoda, Anostraca) is an omnivorous filter feeder whose life span lasts no more than 12 weeks. Adult males and females of E. grubii were used for ultrastructural studies of the midgut epithelium and an analysis of autophagy. The midgut epithelium is formed by columnar digestive cells and no regenerative cells were observed. A distinct regionalization in the distribution of organelles appears - basal, perinuclear and apical regions were distinguished. No differences in the ultrastructure of digestive cells were observed between males and females. Autophagic disintegration of organelles occurs throughout the midgut epithelium. Degenerated organelles accumulate in the neighborhood of Golgi complexes, and these complexes presumably take part in phagophore and autophagosome formation. In some cases, the phagophore also surrounds small autophagosomes, which had appeared earlier. Fusion of autophagosomes and lysosomes was not observed, but lysosomes are enclosed during autophagosome formation. Autophagosomes and autolysosomes are discharged into the midgut lumen due to apocrine secretion. Autophagy plays a role in cell survival by protecting the cell from cell death.


Subject(s)
Anostraca/physiology , Animals , Anostraca/ultrastructure , Autophagy , Czech Republic , Epithelium/physiopathology , Epithelium/ultrastructure , Female , Gastrointestinal Tract/physiology , Gastrointestinal Tract/ultrastructure , Male , Microscopy, Electron, Transmission , Phagosomes/ultrastructure
10.
Bull Environ Contam Toxicol ; 81(5): 485-9, 2008 Nov.
Article in English | MEDLINE | ID: mdl-18777155

ABSTRACT

Ecotoxicological effects of the herbicide atrazine and the insecticides endosulfan sulphate and chlorpyrifos were evaluated using a test battery comprising aquatic organisms from different trophic levels. According to the categories established in the EU legislation, atrazine can be considered non-harmful for the species tested, while the insecticides can be considered very toxic for the crustaceans. The results of acute toxicity tests showed that the sensitivity of organisms were as follows: Thamnocephalus platyurus > Daphnia magna > Vibrio fischeri. Chlorpyrifos may act as a toxic compound in the aquatic environment of Guadiana River, as it may be detected in water at levels that promote toxic effects.


Subject(s)
Aliivibrio fischeri/drug effects , Anostraca/physiology , Atrazine/toxicity , Chlorpyrifos/toxicity , Daphnia/physiology , Endosulfan/toxicity , Herbicides/toxicity , Insecticides/toxicity , Water Pollutants, Chemical/toxicity , Animals , Portugal , Potassium Dichromate/toxicity , Seawater/analysis
11.
Article in English | MEDLINE | ID: mdl-17454375

ABSTRACT

Flexible biodegradable polyurethane foams (BIO-PUR) were prepared by a one-shot process using commercially available coreactants and modified by substituting biodegradable additive based on the acetylated starch (AS), acetylcellulose (AC), 2-hydroxyethylcellulose (HEC) and carboxymethylcellulose sodium salt (CMC) for 5 or 10 wt% of commercial polyether polyol. The BIO-PUR foams were characterized by FTIR, TGA and polarization microscopy. Ecotoxicity of BIO-PUR foams freshwater extracts was evaluated using the alternative crustacean toxicity test Thamnotoxkit F. Values of toxicity were expressed as percentage mortality of the instars II-III larvae of freshwater fairy shrimps (Thamnocephalus platyurus) dependence on the effect criterion of the respective assay. The leaches of BIO-PUR foams modified with 5 or 10 wt% of HEC showed higher toxicity then other BIO-PUR foams, whereas leaches of BIO-PUR with 5wt% of AS and 10wt% of AC were even less toxic than REF. PUR foam.


Subject(s)
Environmental Pollutants/chemistry , Environmental Pollutants/toxicity , Polyurethanes/chemistry , Polyurethanes/toxicity , Animals , Anostraca/drug effects , Anostraca/physiology , Biodegradation, Environmental , Larva/drug effects , Materials Testing , Microspheres , Spectroscopy, Fourier Transform Infrared , Time Factors , Toxicity Tests, Acute
12.
Arch Environ Contam Toxicol ; 52(4): 483-8, 2007 May.
Article in English | MEDLINE | ID: mdl-17387424

ABSTRACT

The aim of this study was to evaluate and compare the toxicity of spent metalworking fluids (MWFs) and two different effluents obtained by biologic and electrochemical treatment of spent MWFs toward aquatic organisms of different trophic levels. The obtained toxicity data was used to calculate safe concentrations of both effluents. The spent MWFs without treatment showed the highest toxicity among the tested samples and should be classified as "extremely toxic" (toward invertebrates) or "very toxic" (toward other test organisms). Both methods applied for MWFs treatment resulted in a significant decrease in toxicity of the treated MWFs, but the obtained effluents had still to be regarded as "toxic". The ranges of the values of acute toxic units for both effluents were significantly narrower than for the untreated spent MWFs. The values of the safe concentrations of the spent MWFs, the biologic effluent, and the water phase resulting from electrochemical emulsion breaking were equal to 0.013%, l.8%, and 1.3%, respectively, corresponding to chemical oxygen demand concentrations of 1.8%, 32, and 34 mg O(2)*L(-1). These values are far lower than the discharging limit of 125 mg O(2)*L(-1) for industrial effluents, according to the relevant Polish regulations. It is therefore recommended to include toxicity bioassay parameters into guidelines for wastewater discharges to surface waters because the existing chemical and physical parameters are not sufficient to describe the environmental impact of industrial wastewater. Toxicity bioassays can be a promising tool for evaluating the efficacy of unit operations in industrial wastewater treatment (toxicity reduction evaluation) as well as identification of toxic substances in effluents (toxicity identification evaluation).


Subject(s)
Industrial Oils/toxicity , Industrial Waste/adverse effects , Water Pollutants, Chemical/toxicity , Aliivibrio fischeri/drug effects , Aliivibrio fischeri/metabolism , Animals , Anostraca/drug effects , Anostraca/physiology , Chlorophyta/drug effects , Chlorophyta/growth & development , Daphnia/drug effects , Daphnia/physiology , Electrochemistry , Lethal Dose 50 , Luminescence , Poecilia/physiology , Waste Disposal, Fluid/methods
13.
Environ Toxicol ; 22(1): 64-8, 2007 Feb.
Article in English | MEDLINE | ID: mdl-17295262

ABSTRACT

Cyanobacteria occur widely in lakes, reservoirs, ponds, and slow flowing rivers. Many species are known to produce toxins (cyanotoxins), a number of which are of concern for health. Cyanotoxins vary in chemical structure and may be found intracellular or released into water. There is not only a wide variation in the toxicity of known cyanotoxins but a substantial number of toxins have to date not been identified chemically. Chemical analysis of cyanotoxins is nowadays not used for routine monitoring because it is time consuming, it requires specialized equipment and expertise, and is hence expensive. There is hence an urgent need for rapid tests in surface waters to detect cyanobacterial toxins because of the need for safe drinking water and safe natural bathing waters, which may be burdened by cyanobacterial blooms or scums. Previous investigations have already shown that larvae of the anostracan crustacean Thamnocephalus platyurus are quite sensitive to neurotoxic and hepatotoxic cyanotoxins. The present paper reports on the sensitivity comparison of the (1 h) Rapidtoxkit (based on a sublethal endpoint) and the (24 h) Thamnotoxkit microbiotest (based on mortality). Both assays make use of larvae of T. platyurus. The Rapidtoxkit is a new microbiotest that determines the decrease of ingestion of colored particles by the crustacean larvae, which are stressed by a short exposure to toxicants. Fifteen cyanobacterial samples composed of laboratory strains and natural bloom samples were tested by both microbiotests. All samples were also analyzed concurrently by HPLC for microcystins and cylindrospermopsin. The correlation coefficient between the two microbiotests (r = 0.82) showed the very good correspondence between the sublethal and the lethal effects. No known toxins could be detected in some samples, although the latter were found highly toxic to the test organisms in both bioassays. These results point to the presence of unknown toxin(s) produced by some cyanobacteria such as e.g., the Cylindrospermopsis raciborskii strain isolated from Lake Balaton in Hungary. This comparative study clearly showed that the 1 h Rapidtoxkit is an attractive rapid alternative to the Thamnotoxkit microbiotest.


Subject(s)
Anostraca/drug effects , Bacterial Toxins/analysis , Larva/drug effects , Marine Toxins/analysis , Microcystins/analysis , Toxicity Tests/methods , Water Microbiology , Water Pollutants/toxicity , Alkaloids , Animals , Anostraca/physiology , Biological Assay/methods , Chromatography, High Pressure Liquid , Cyanobacteria Toxins , Hungary , Larva/physiology , Lethal Dose 50 , Uracil/analogs & derivatives , Uracil/analysis , Water Pollutants/analysis
14.
Environ Sci Pollut Res Int ; 13(1): 22-7, 2006 Jan.
Article in English | MEDLINE | ID: mdl-16417128

ABSTRACT

BACKGROUND, AIMS AND SCOPE: In view of the limited amount of information on the potential hazard of the ever increasing amounts of drugs in surface waters to aquatic biota, a study was undertaken to determine the effect levels of 28 selected pharmaceuticals to the crustacean test species Thamnocephalus platyurus. The drugs belong to 5 different groups: non steroidal anti-inflammatory agents, biocides, cardiovascular compounds, nervous system drugs and pu rine alkaloids METHODS: Toxicity tests were carried out with the 1h Rapidtoxkit and the 24h Thamnotoxkit microbiotests in order to make a comparison of sublethal effects (visible as stress through absence of feeding) measured after a very short time of exposure (1h) and lethal effects after prolonged exposure (24h). Dilution series starting at 200 mg l(-1) were prepared and applied, and median effects levels were calculated and transformed into Toxic Units (TU) for easy data comparison. RESULTS AND DISCUSSION: The toxic effects found have been ranked into 4 arbitrary toxicity classes: not toxic (TU<0.2), low toxicity (0.210). The toxicity levels noted ranged from virtually no effects for a few of the pharmaceuticals, at the highest concentration tested out, to LC50's below 1 mg l(-1) (>100 TU) for 3 nervous system drugs (Amitryptiline, Thioridazine and Chlorpromazine). According to the toxicity classification, 17 of the 28 compounds (i.e. 67%), belong to the same class for the lethal and the sublethal tests. More pronounced differences in effect levels between the two assays were observed mainly for the pharmaceuticals which were either not toxic or only slightly toxic at the 200 mg l(-1) level. For 90% of the toxic drugs the ratio between the toxicity values for both tests is below 5. CONCLUSION: An overall correlation coefficient of 0.96 was found between the 2 microbiotests, confirming the good predictive potential of the 1h stress-based Rapidtoxkit in revealing important biological effects (mortality) after more prolonged exposure of the crustacean test species to chemical compounds. RECOMMENDATION AND OUTLOOK: The present study clearly shows that new microbiotests such as the 1h Rapidtoxkit and the 24h Thamnotoxkit are attractive tools for rapid cost-effective screening of 'new' pollutants such as drugs which may threaten the biological communities of the aquatic environment.


Subject(s)
Anostraca/drug effects , Toxicity Tests, Acute , Animals , Anostraca/physiology , Color , Eating/drug effects , Larva/drug effects , Larva/physiology , Lethal Dose 50 , Microspheres , Toxicology/methods
SELECTION OF CITATIONS
SEARCH DETAIL
...