scholarly journals Diatom Deformities and Tolerance to Cadmium Contamination in Four Species

Environments ◽  
2019 ◽  
Vol 6 (9) ◽  
pp. 102
Author(s):  
Sandra Kim Tiam ◽  
Isabelle Lavoie ◽  
Fengjie Liu ◽  
Paul B. Hamilton ◽  
Claude Fortin
Keyword(s):  
Metal Tolerance ◽  
Effective Quantum Yield ◽  
Sensitive Species ◽  
Nitzschia Palea ◽  
Relative Tolerance ◽  
Abnormal Cells ◽  
Exposure Experiment ◽  
Tolerance To Cadmium ◽  
Short Time ◽  
Photosynthetic Capacities

The relative tolerance of four diatoms (Nitzschia palea, Pinnularia mesolepta, Mayamaea atomus, and Gomphonema truncatum) to Cd was evaluated, including their proneness to deformities, and the severity of the abnormalities in relation to Cd concentration. The indirect effect of Cd on photosynthetic capacities was assessed during a short time exposure experiment using a dose-response approach to evaluate the relative tolerance of the four diatom species. The EC25 were 9 (3, 23), 606 (348, 926), 1179 (1015, 1349) and 2394 (1890, 2896) µg/L for P. mesolepta, G. truncatum, N. palea, and M. atomus respectively. P. mesolepta was by far the most Cd sensitive species while M. atomus was the most tolerant. In addition, diatoms were exposed to a single concentration of Cd comparable to a heavily contaminated environment for a longer duration to evaluate the effect of Cd on growth kinetics and the deformities induced. N. palea, P. mesolepta, and M. atomus were able to grow when cultivated with Cd while G. truncatum was not. Cadmium strongly affected the effective quantum yield in G. truncatum (4.8 ± 5.9% of the control) and P. mesolepta cultures (29.2 ± 6.9% of the control). The effects were moderate for N. palea (88.3 ± 0.7% of the control) and no impact was observed for M. atomus. The results from the two approaches were in accordance since they identified N. palea and M. atomus as the two most tolerant species to Cd, while P. mesolepta and G. truncatum were the most sensitive. The microscopy analyses revealed that P. mesolepta was more impacted by Cd than N. palea and M. atomus considering both the quantity of abnormal cells and the severity of the deformities. Overall, this research shows that not all deformities can be considered equal for a water quality bio-assessment. The work highlights a need to take into account metal-tolerance/sensitivity of the species and the severity of the deformities.

Cadmium chelation by frustulins: a novel metal tolerance mechanism in Nitzschia palea (Kützing) W. Smith

Ecotoxicology ◽  
2012 ◽  
Vol 22 (1) ◽  
pp. 166-173 ◽  
Author(s):  
José Santos ◽  
Salomé F. P. Almeida ◽  
Etelvina Figueira
Keyword(s):  
Metal Tolerance ◽  
Tolerance Mechanism ◽  
Nitzschia Palea

scholarly journals PHOTOSYNTHETIC PARAMETERS AS PHYSIOLOGICAL INDICATORS OF TOLERANCE TO CADMIUM STRESS IN SUNFLOWER GENOTYPES

2018 ◽  
Vol 31 (4) ◽  
pp. 907-916 ◽  
Author(s):  
Bárbara Lima do Sacramento ◽  
André Dias de Azevedo Neto ◽  
Andréia Teixeira Alves ◽  
Silvany Cardim Moura ◽  
Rogério Ferreira Ribas
Keyword(s):  
Stomatal Conductance ◽  
Quantum Yield ◽  
Nutrient Solution ◽  
Photosynthetic Pigment ◽  
Photosynthetic Parameters ◽  
Effective Quantum Yield ◽  
Cd Stress ◽  
Physiological Indicators ◽  
Net Assimilation ◽  
Tolerance To Cadmium

ABSTRACT The objective of the present study was to evaluate the tolerance to cadmium (Cd) of sunflower genotypes grown in greenhouse conditions, and the effectiveness of using photosynthetic parameters as physiological indicators of this tolerance. Seeds of two sunflower genotypes previously identified as tolerant (H358) and Cd-sensitive (AG960) to Cd were used. The seeds were germinated in plastic cups containing plant substrate; after 9 days, the seedlings were transplanted to plastic basins containing a nutrient solution with 0 or 10 µM of Cd, where they remained for 16 days. Samples of the plants were harvested every 5 days. The experiment was carried out in a randomized complete design, using a 4×2×2 factorial arrangement (4 days of grown in a nutrient solution with Cd, 2 sunflower genotypes, and 2 Cd levels) with four replications. Cd stress decreased CO2 net assimilation, stomatal conductance, carboxylation efficiency, photosynthetic pigment contents, potential quantum yield (Fv/Fm), and effective quantum yield of plants of the two evaluated genotypes. The decrease in photosynthetic rates of these plants was caused by both stomatal and non-stomatal limitations. Plants of the AG960 genotype showed more pronounced deleterious effects due to Cd stress than those of the H358 genotype. Thus, CO2 net assimilation rate, stomatal conductance, and chloroplast pigment content are good physiological indicators of sunflower tolerance to Cd and can at least in part, explain the greater tolerance of the H358 genotype to Cd stress when compared to the AG960 genotype.

Integration of environmental and fishery management in Europe

2012 ◽  
Vol 69 (8) ◽  
pp. 1329-1332 ◽  
Author(s):  
Simon Jennings ◽  
Will J. F. Le Quesne
Keyword(s):  
Fishery Management ◽  
Ecosystem Functions ◽  
State Function ◽  
Sensitive Species ◽  
Relevant Evidence ◽  
Management Measures ◽  
Main Challenge ◽  
Management Plans ◽  
Short Time ◽  
Fishing Impacts

Abstract Jennings, S., and Le Quesne, W. J. F. 2012. Integration of environmental and fishery management in Europe. – ICES Journal of Marine Science, 69: . Policy drivers for integrating environmental and fishery management in Europe have never been so strong. Scientists calling for better integration now have the opportunity to help deliver it. The main challenge is providing relevant evidence on short time-scales using existing knowledge. Policies, scientists, and society largely agree that management targets should be linked to achieving sustainability, but research often fails to show when fishing impacts ‘matter’ in relation to sustainability criteria. If targets for ecosystem functions or processes are to complement more tractable targets for species and habitats, scientists will need to show why impacts ‘matter’ and when they become unsustainable. For now, and to meet ambitious and pressing policy timetables, priority should be given to developing credible targets for impacts with a high risk of compromising sustainability, rather than dissipating research and advisory effort to achieve broader coverage of state, function, and process. Impacts on sensitive species and habitats often compromise sustainability; thus, setting targets for them is a priority. Meeting these targets will often require management measures that are expected to diminish risks of other unsustainable impacts. Fast and significant progress towards integration could be achieved by incorporating measures to meet environmental targets for sensitive species and habitats into fishery management plans.

scholarly journals Lamina Cell Shape and Cell Wall Thickness Are Useful Indicators for Metal Tolerance—An Example in Bryophytes

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 274
Author(s):  
Katharina Petschinger ◽  
Wolfram Adlassnig ◽  
Marko S. Sabovljevic ◽  
Ingeborg Lang
Keyword(s):  
Cell Wall ◽  
Wall Thickness ◽  
Cell Walls ◽  
Cell Shape ◽  
Metal Tolerance ◽  
Heavy Metal Tolerance ◽  
Cell Wall Thickness ◽  
Pleurozium Schreberi ◽  
Sensitive Species ◽  
Good Marker

Bryophytes are widely used to monitor air quality. Due to the lack of a cuticle, their cells can be compared to the roots of crop plants. This study aimed to test a hypothetical relation between metal tolerance and cell shape in biomonitoring mosses (Hypnum cupressiforme, Pleurozium schreberi, Pseudoscleropodium purum) and metal sensitive species (Physcomitrium patens, Plagiomnium affine). The tolerance experiments were conducted on leafy gametophytes exposed to solutions of ZnSO4, ZnCl2, and FeSO4 in graded concentrations of 1 M to 10−8 M. Plasmolysis in D-mannitol (0.8 M) was used as a viability measure. The selected species differed significantly in lamina cell shape, cell wall thickness, and metal tolerance. In those tested mosses, the lamina cell shape correlated significantly with the heavy metal tolerance, and we found differences for ZnSO4 and ZnCl2. Biomonitoring species with long and thin cells proved more tolerant than species with isodiametric cells. For the latter, “death zones” at intermediate metal concentrations were found upon exposure to ZnSO4. Species with a greater tolerance towards FeSO4 and ZnSO4 had thicker cell walls than less tolerant species. Hence, cell shape as a protoplast-to-wall ratio, in combination with cell wall thickness, could be a good marker for metal tolerance.

scholarly journals Photoacclimation in three species of freshwater red algae

2007 ◽  
Vol 19 (1) ◽  
pp. 23-34 ◽  
Author(s):  
Anna I.N. Bautista ◽  
Orlando Necchi Jr.
Keyword(s):  
Quantum Yield ◽  
High Irradiance ◽  
Photochemical Quenching ◽  
Effective Quantum Yield ◽  
Low Light ◽  
Recovery Capacity ◽  
Long Time ◽  
Freshwater Red Algae ◽  
Non Photochemical Quenching ◽  
Short Time

Three freshwater Rhodophyta species (Audouinella eugenea, A. hermannii and Compsopogon coeruleus) were tested as to their responses (photosynthesis, growth and pigment concentration) to two irradiances (low light, LL, 65 µmol m-2 s-1 and high light, HL, 300 µmol m-2 s-1) and two periods (short time, ST, 4 d, and long time, LT, 28 d). Higher growth rates were consistently observed at LL but significant differences were observed only for A. hermannii. Higher values of photoinhibition at LL were found for the three species, which is consistent with the dynamic photoinhibition as a reversible photoprotective mechanism against high irradiance. Light-induced decreases of effective quantum yield (EQY) were observed in the three species consisting of pronounced decreases from LL to HL. Rapid increases of non-photochemical quenching (NPQ) were observed mainly at LL, indicating energy dissipation by reaction centers. Results revealed distinct photoacclimation strategies to deal with high irradiances: the two Audouinella species had only characteristics of shade-adapted algae: acclimation by changes of size of photosystem units (PSU) under LT and by PSU number under ST; higher values of the photoinhibition parameter (beta) and NPQ, and lower values of EQY at LL; higher recovery capacity of potential quantum yield (PQY) at LL and under ST; highly significant positive correlation of electron transport rate (ETR) with NPQ. In addition, C. coeruleus mixed some characteristics of sun-adapted algae: acclimation by changes of PSU number under LT and by PSU size under ST; higher recovery capacity of EQY than the other two species; weak or no correlation of ETR with NPQ. Thus, these characteristics indicate that C. coeruleus cope with high irradiances more efficiently than the Audouinella species.

scholarly journals Computer-Assisted Reconstruction and Motion Analysis of the Three-Dimensional Cell

2003 ◽  
Vol 3 ◽  
pp. 827-841 ◽  
Author(s):  
David R. Soll ◽  
Deborah Wessels ◽  
Paul J. Heid ◽  
Edward Voss
Keyword(s):  
3D Reconstruction ◽  
Motion Analysis ◽  
Three Dimensional ◽  
Computer Assisted ◽  
3D Analysis ◽  
Time Intervals ◽  
Abnormal Cells ◽  
3D Information ◽  
Short Time ◽  
Microscopic Techniques

Even though several microscopic techniques provide three-dimensional (3D) information on fixed and living cells, the perception persists that cells are two-dimensional (2D). Cells are, in fact, 3D and their behavior, including the extension of pseudopods, includes an important 3D component. Although treating the cell as a 2D entity has proven effective in understanding how cells locomote, and in identifying defects in a variety of mutant and abnormal cells, there are cases in which 3D reconstruction and analysis are essential. Here, we describe advanced computer-assisted 3D reconstruction and motion analysis programs for both individual live, crawling cells and developing embryos. These systems (3D-DIAS, 3D-DIASemb) can be used to reconstruct and motion analyze at short time intervals the nucleus and pseudopodia as well as the entire surface of a single migrating cell, or every cell and nucleus in a developing embryo. Because all images are converted to mathematical representations, a variety of motility and dynamic morphology parameters can be computed that have proven quite valuable in the identification of mutant behaviors. We also describe examples of mutant behaviors in Dictyostelium that were revealed through 3D analysis.

scholarly journals Protein lysine methylation is involved in modulating the response of sensitive and tolerant Arabidopsis species to cadmium stress

2019 ◽  
Author(s):  
Nelson B.C. Serre ◽  
Manon Sarthou ◽  
Océane Gigarel ◽  
Sylvie Figuet ◽  
Massimiliano Corso ◽  
...  
Keyword(s):  
Cadmium Stress ◽  
Cadmium Accumulation ◽  
Lysine Methylation ◽  
Wild Type ◽  
Sensitive Species ◽  
Lysine Residues ◽  
Methyltransferase Gene ◽  
Lysine Methyltransferase ◽  
Tolerance To Cadmium ◽  
Arabidopsis Species

ABSTRACTThe mechanisms underlying the response and adaptation of plants to excess of trace elements are not fully described. Here, we analyzed the importance of protein lysine methylation for plants to cope with cadmium. We analyzed the effect of cadmium on lysine-methylated proteins and protein lysine methyltransferases (KMTs) in two cadmium-sensitive species, Arabidopsis thaliana and A. lyrata, and in three populations of A. halleri with contrasting cadmium accumulation and tolerance traits. We showed that some proteins are differentially methylated at lysine residues in response to Cd and that a few genes coding KMTs is regulated by cadmium. Also, we showed that nine out of 23 A. thaliana mutants interrupted in KMT genes have a tolerance to cadmium that is significantly different from that of wild-type seedlings. We further characterized two of these mutants, one was knocked-out in the calmodulin lysine methyltransferase gene and displayed increased tolerance to cadmium, the other was interrupted in a KMT gene of unknown function and showed a decreased capacity to cope with cadmium. Together, our results showed that lysine methylation of non-histone proteins is impacted by cadmium and that several methylation events are important for modulating the response of Arabidopsis plants to cadmium stress.

What the replication reformation wrought

2018 ◽  
Vol 41 ◽  
Author(s):  
Barbara A. Spellman ◽  
Daniel Kahneman
Keyword(s):  
Reform Movement ◽  
Short Time

AbstractReplication failures were among the triggers of a reform movement which, in a very short time, has been enormously useful in raising standards and improving methods. As a result, the massive multilab multi-experiment replication projects have served their purpose and will die out. We describe other types of replications – both friendly and adversarial – that should continue to be beneficial.

Periodic Variations in the Coronal Green Line Intensity and their Connection with the White-light Coronal Structures

2000 ◽  
Vol 179 ◽  
pp. 197-200
Author(s):  
Milan Minarovjech ◽  
Milan Rybanský ◽  
Vojtech Rušin
Keyword(s):  
Time Resolution ◽  
White Light ◽  
Short Time Scale ◽  
High Time Resolution ◽  
Green Line ◽  
Periodic Intensity ◽  
Coronal Green Line ◽  
Significant Intensity ◽  
Short Time ◽  
Coronal Structures

AbstractWe present an analysis of short time-scale intensity variations in the coronal green line as obtained with high time resolution observations. The observed data can be divided into two groups. The first one shows periodic intensity variations with a period of 5 min. the second one does not show any significant intensity variations. We studied the relation between regions of coronal intensity oscillations and the shape of white-light coronal structures. We found that the coronal green-line oscillations occur mainly in regions where open white-light coronal structures are located.

Destruction of Actin Filaments by Osmium Tetroxide

1977 ◽  
Vol 35 ◽  
pp. 466-467
Author(s):  
P. Maupin-Szamier ◽  
T. D. Pollard
Keyword(s):  
Actin Filaments ◽  
Time Course ◽  
Osmium Tetroxide ◽  
Rabbit Muscle ◽  
Muscle Actin ◽  
Sodium Phosphate Buffer ◽  
Transmission Electron ◽  
The Difference ◽  
Rates Of Decay ◽  
Short Time

We have studied the destruction of rabbit muscle actin filaments by osmium tetroxide (OSO4) to develop methods which will preserve the structure of actin filaments during preparation for transmission electron microscopy.Negatively stained F-actin, which appears as smooth, gently curved filaments in control samples (Fig. 1a), acquire an angular, distorted profile and break into progressively shorter pieces after exposure to OSO4 (Fig. 1b,c). We followed the time course of the reaction with viscometry since it is a simple, quantitative method to assess filament integrity. The difference in rates of decay in viscosity of polymerized actin solutions after the addition of four concentrations of OSO4 is illustrated in Fig. 2. Viscometry indicated that the rate of actin filament destruction is also dependent upon temperature, buffer type, buffer concentration, and pH, and requires the continued presence of OSO4. The conditions most favorable to filament preservation are fixation in a low concentration of OSO4 for a short time at 0°C in 100mM sodium phosphate buffer, pH 6.0.

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