22 research outputs found
Tolerance to ammonia of Thulinius ruffoi (Bertolani, 1981), a tardigrade isolated from a sewage treatment plant
The acute toxicity of ammonia on Thulinius ruffoi (Bertolani, 1981), a eutardigrade isolated from a small waste water treatment plant (WWTP) in Poland, was estimated. Our results show that no active individuals survived a 24聽h exposure to solutions equal to or higher than 125聽mg/L of total ammonia nitrogen (NH(3)鈥揘聽+聽NH(4)(+)鈥揘), which, under the conditions in our experiment, was equivalent to 1.17聽mg/L of un-ionised ammonia (NH(3)). The LC(50) concentration of total ammonia nitrogen was equal to 52聽mg/L (or 0.65聽mg/L un-ionised ammonia). Given that the norms for the concentration of ammonia in treated waters leaving WWTPs are usually several times lower than the LC(50) for T. ruffoi, this species does not seem to be a good bioindicator candidate for WWTPs. In this paper we also note that various ecotoxicological studies use different methodological approaches and we suggest that a more uniform methodology may aid interspecific comparisons of LC(50) values
Critical factors besides treatment dose and duration need to be controlled in Pb toxicity tests in plant cell suspension cultures
The study was designed to determine the proper conditions for suspension culture of Viola tricolor cells in toxicity studies of Pb at different concentrations (0, 200, 500, 1000, 2000 \mu M) and exposure times (24, 48, 72 h). By forming insoluble salts with ions from the medium, lead (II) nitrate added to the medium decreased the initial 5.7-5.8 pH of the medium, depending on the Pb salt concentration and light intensity. In alamarBlue assays, we found no dose- or time-dependent effect of Pb on cell viability when we did not adjust pH and did not standardize the illumination conditions to correct the effect of lead-salt-induced turbidity. When effective illumination was adjusted to correct for turbidity at the highest lead concentration and pH was adjusted to 5.7-5.8, cell viability decreased with the increase of Pb(NO_{3})_{2} concentration and with treatment time. These experiments demonstrate that the toxic action of lead on cells in suspension depends strongly on culture conditions, and not only on the metal concentration and duration of treatment
Reducing flower competition for assimilates by half results in higher yield of Fagopyrum esculentum
Despite abundant flowering throughout the season, common buckwheat develops a very low number of kernels probably due to competition for assimilates. We hypothesized that plants with a shorter flowering period may give a higher seed yield. To verify the hypothesis, we studied nutrient stress in vitro and in planta and analyzed different embryological and yield parameters, including hormone profile in the flowers. In vitro cultivated flowers on media with strongly reduced nutrient content demonstrated a drastic increase in degenerated embryo sacs. In in planta experiments, where 50% or 75% of flowers or all lateral ramifications were removed, the reduction of the flower competition by half turned out to be the most promising treatment for improving yield. This treatment increased the frequency of properly developed embryo sacs, the average number of mature seeds per plant, and their mass. Strong seed compensation under 50% inflorescence removal could result from increased production of salicylic and jasmonic acid that both favor more effective pollinator attraction. Plants in single-shoot cultivation finished their vegetation earlier, and they demonstrated greater single seed mass per plant than in control. This result suggests that plants of common buckwheat with shorter blooming period could deliver higher seed yield
Stable artificial autopolyploids of the Zn/Cd accumulator Arabidopsis arenosa : a promising genetic resource for phytoremediation
Diseases caused by protozoa of the genus Trypanosoma (Excavate, Euglenozoa).
艢pi膮czka afryka艅ska jest chorob膮 wywo艂ywan膮 przez pierwotniaki Trypanosoma brucei gambiense i Trypanosoma brucei rhodesiense, w jej ameryka艅skiej odmianie przez Trypanosoma cruzi. Paso偶yty te s膮 jednokom贸rkowymi pierwotniakami, kt贸re maj膮 z艂o偶ony cykl 偶yciowy i posiadaj膮 dw贸ch 偶ywicieli, z kt贸rych jednym jest cz艂owiek. 艢widrowce te butuj膮 we krwi cz艂owieka, jednak w p贸藕nych etapach infekcji mog膮 zasiedla膰 tak偶e p艂yn m贸zgowo-rdzeniowy, i wywo艂ywa膰 tak zwan膮 艣pi膮czk臋. W organizmie 偶ywiciela po艣redniego i ostatecznego paso偶yty przyjmuj膮 szereg postaci. Choroba ta prowadzi cz臋sto do 艣mierci, cho膰 jest mo偶liwa do wyleczenia zw艂aszcza w pierwszych etapach infekcji. Mo偶e ona zosta膰 zwalczona 艣rodkami farmakologicznymi, jednak nie s膮 one oboj臋tne dla zdrowia cz艂owieka, dlatego kluczow膮 rol臋 odgrywa stosowanie 艣rodk贸w zapobiegawczych, eliminuj膮cych znacznie ryzyko wyst膮pienia choroby.Sleeping sickness is a disease caused by the protozoan Trypanosoma brucei gambiense and Trypanosoma brucei rhodesiense, in its American variant by the Trypanosoma cruzi. These parasites are unicellular protozoa, which have complex life cycle and have got two hosts, one of which is human. These trypanosomes occur in human blood, but in the late stages of infection can also colonize the cerebrospinal fluid and cause the so-called coma. In the body, the final and intermediate host, parasite take a number of forms. This disease often leads to death, although it is possible to cure especially in the early stages of infection. It can be eradicated with drugs, but they are not indifferent to human health, and therefore plays a key role preventative measures, eliminating risk of disease
Akumulacja metali i tolerancja na cynk i o艂贸w kom贸rek w kulturze zawiesinowej gatunk贸w Viola L. z gleb metalono艣nych i niemetalono艣nych : konstytutywna tolerancja na metale ci臋偶kie w rodzaju Viola
Phenotypic plasticity in taxonomic traits of the tardigrade Diphascon higginsi BINDA, 1971 (Tardigrada: Eutardigrada: Hypsibiidae)
Niesporczaki (Tardigrada) to typ bezkr臋gowc贸w zaliczanych do wylinkowc贸w (Ecdysozoa). Zasiedlaj膮 one przede wszystkim 艣rodowisko wodne, przy czym 偶yj膮 zar贸wno w wodach s艂odkich jak i s艂onych, oraz l膮dowe, gdzie 偶yj膮 zwykle w 艣rodowisku o wysokiej wilgotno艣ci, jakiej dostarczaj膮 im mchy b膮d藕 porosty. Organizmy te cechuj膮 si臋 wysok膮 odporno艣ci膮 na ekstremalne warunki 艣rodowiskowe, takie jak dehydratacja czy niskie i wysokie temperatury. Pozycja systematyczna niesporczak贸w jest stosunkowo niejasna. Typ ten obejmuje trzy gromady: Heterotardigrada, Mesotardigrada i Eutardigrada.W poni偶szej pracy skupi艂am si臋 na gatunku Diphascon higginsi BINDA, 1971, nale偶膮cym do gromady Eutardigrada, kt贸ry obejmuje przede wszystkim gatunki l膮dowe i s艂odkowodne. Celem serii eksperyment贸w opisanej w niniejszej pracy by艂o oszacowanie plastyczno艣ci fenotypowej w morfometrycznych cechach wa偶nych taksonomicznych, wzgl臋dem temperatury i dost臋pno艣ci po偶ywienia. W pocz膮tkowym etapie eksperymentu z jednej partenogenetycznej samicy wyprowadzono klonalny szczep D. higginsi, co umo偶liwi艂o zinterpretowanie zaobserwowanej zmienno艣ci jako plastyczno艣ci fenotypowej. W eksperymencie zosta艂o wykorzystanych pi臋膰 zabieg贸w 艣rodowiskowych: sta艂e temperatury 8掳C, 16掳C, 20掳C, temperatura fluktuuj膮ca (cyklicznie 8-16-20-16-8 掳C) oraz zabieg z ograniczon膮 dost臋pno艣ci膮 pokarmu (w 16 掳C). 艁膮cznie uzyskano 540 osobnik贸w, z kt贸rych uzyskano oko艂o 4300 pomiar贸w cech taksonomicznych.Plastyczno艣膰 fenotypowa u w klonalnej populacji D. higginsi okaza艂a si臋 by膰 znacz膮ca, jednak bez istotnych r贸偶nic pomi臋dzy przeprowadzonymi zabiegami w 艣rednich i zakresach rozmiar贸w zmierzonych struktur. Wyniki uzyskane w niniejszej pracy by艂y eksperymentalnym testem dla zasadno艣ci przeprowadzania tradycyjnych analiz taksonomicznych z u偶yciem metod morfometrycznych.Water bears (Tardigrada) are a phylum of invertebrates that belong to moulting animals (Ecdysozoa). They live in aquatic environments, both in marine and freshwater habitats. However, they also dwell in terrestrial environments with high humidity, such as mosses and lichens. These organisms are highly resistant to extreme environmental conditions, such as dehydration or low and high temperatures. The phylogenetic position of tardigrades is relatively uncertain. The phylum comprises three orders: Heterotardigrada, Mesotardigrada and Eutardigrada.In this paper I focused on a eutardigrade species, Diphascon higginsi BINDA, 1971. The aim of the series of experiments described in this thesis was to estimate phenotypic plasticity in taxonomically important morphometric traits in relation to temperature and food availability. Before the experiments started, a clonal strain of D. higginsi was established using a single parthenogenetic female. This made it possible to interpret the observed variance in morphometric traits as phenotypic plasticity. The study consisted of five environmental treatments: stable 8掳C, 16掳C, 20掳C, a fluctuating temperature (cycles of 8-16-20-16-8 掳C) and periodic starvation (at 16 掳C). In total, 540 individuals were obtained, which allowed ca. 4300 morphometric measurements.Phenotypic plasticity in the examined clonal population of D. higginsi was considerable, but there were no significant differences between the treatments either in means or ranges for the measured traits. The results obtained in this study were a test for methods of traditional taxonomy that relies on morphometric measurements
Garden pansy (Viola 脳 wittrockiana Gams.) : a good candidate for the revitalisation of polluted areas
In the current studies, heavy metal tolerance level, accumulation efficiency and sexual reproduction were determined in Viola 脳 wittrockiana, a non-metallophytic ornamental cultivar in comparison to V. tricolor, a metallo-
phyte, after zinc (Zn) or lead (Pb) treatment (0, 10, 100 and 1 000 ppm) in pot experiments. The seed germination frequency that was not reduced in comparison to the control, the effective Zn absorption from the soil and exclusion strategy for Pb, as well as the regular sexual reproduction of V. 脳 wittrockiana treated with heavy metals all indicate the tolerance of this plant to heavy metals. The lack of a seed set under experimental conditions of V. 脳 wittrockiana
was due to the absence of pollinators, rather than the negative impact of heavy metals, as pollen viability and ovule
development were normal under the treatments. The results indicate that V. 脳 wittrockiana represents similar
tolerance to Viola metallophytes and could be considered as a good material for the reclamation of polluted areas. The exceptional tolerance to heavy metals, the ability to initiate new generations in heavy-metal-burdened soil, which are additionally coupled with the unique beauty, make the garden pansy a good candidate to be potentially used
in the future for phytoremediation purposes
Cell suspension cultures as a model in studies of plant tolerance to heavy metals
Zanieczyszczenia gleby metalami ci臋偶kimi maj膮 toksyczne dzia艂anie na ro艣liny, zwierz臋ta oraz cz艂owieka. Metalofity, ro艣liny odporne na metale ci臋偶kie, kolonizuj膮ce tereny metalono艣ne, s膮 wykorzystywane do fitoremediacji, czyli oczyszczania gleb z metali ci臋偶kich. Wykorzystanie ro艣linnych kultur kom贸rkowych do bada艅 nad toksyczno艣ci膮 metali i tolerancj膮 kom贸rek na ich dzia艂anie jest stosunkowo now膮 technik膮. W pracy zosta艂y przedstawione mo偶liwo艣ci wykorzystania ro艣linnych kultur zawiesinowych w badaniach nad wp艂ywem metali ci臋偶kich na metabolizm kom贸rek oraz metody oszacowania ich toksycznego wp艂ywu. Zaprezentowane zosta艂y techniki otrzymywania kultur zawiesinowych, oceny 偶ywotno艣ci kom贸rek, akumulacji metali ci臋偶kich w kom贸rkach. W ocenie toksyczno艣ci metali stosuje si臋 tak偶e badania nad programowan膮 艣mierci膮 kom贸rki (PCD), co pozwala oszacowa膰 reakcj臋 kom贸rek na ich wysokie st臋偶enia. Zosta艂y przedyskutowane mechanizmy tolerancji kom贸rek na metale ci臋偶kie. Kultury zawiesinowe s膮 dobrym modelem do bada艅 tolerancji na metale, poniewa偶 pozwalaj膮 zbada膰 ich wp艂yw na pojedyncze kom贸rki w jednolitych, sta艂ych warunkach.Soil pollutants exert toxic effects on plants, animals and humans. Metallophytes, plants tolerant to heavy metals colonizing polluted areas, are being used to phytoremediation - cleaning up soil contaminated with heavy metals. The use of plant cells in vitro cultures to study heavy metal toxicity and tolerance is a relatively new approach in research of metal toxicity. In this paper the usefulness of plant suspension cultures to study the impact of heavy metals on cells is presented alongside with the methods of obtaining suspension cultures, evaluation of cell viability, metal accumulation and detection of programmed cell death (PCD). The mechanisms by which cells of plant species tolerant to heavy metals develop resistance to metal toxicity are discussed. Cell suspension cultures appear to be a good model to study tolerance to heavy metals because they allow to estimate metal impact to a single cell in stable uniform conditions
Insights into Plant Programmed Cell Death Induced by Heavy Metals鈥擠iscovering a Terra Incognita
Programmed cell death (PCD) is a process that plays a fundamental role in plant development and responses to biotic and abiotic stresses. Knowledge of plant PCD mechanisms is still very scarce and is incomparable to the large number of studies on PCD mechanisms in animals. Quick and accurate assays, e.g., the TUNEL assay, comet assay, and analysis of caspase-like enzyme activity, enable the differentiation of PCD from necrosis. Two main types of plant PCD, developmental (dPCD) regulated by internal factors, and environmental (ePCD) induced by external stimuli, are distinguished based on the differences in the expression of the conserved PCD-inducing genes. Abiotic stress factors, including heavy metals, induce necrosis or ePCD. Heavy metals induce PCD by triggering oxidative stress via reactive oxygen species (ROS) overproduction. ROS that are mainly produced by mitochondria modulate phytotoxicity mechanisms induced by heavy metals. Complex crosstalk between ROS, hormones (ethylene), nitric oxide (NO), and calcium ions evokes PCD, with proteases with caspase-like activity executing PCD in plant cells exposed to heavy metals. This pathway leads to very similar cytological hallmarks of heavy metal induced PCD to PCD induced by other abiotic factors. The forms, hallmarks, mechanisms, and genetic regulation of plant ePCD induced by abiotic stress are reviewed here in detail, with an emphasis on plant cell culture as a suitable model for PCD studies. The similarities and differences between plant and animal PCD are also discussed