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 h exposure to solutions equal to or higher than 125 mg/L of total ammonia nitrogen (NH(3)–N + NH(4)(+)–N), which, under the conditions in our experiment, was equivalent to 1.17 mg/L of un-ionised ammonia (NH(3)). The LC(50) concentration of total ammonia nitrogen was equal to 52 mg/L (or 0.65 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

Diseases caused by protozoa of the genus Trypanosoma (Excavate, Euglenozoa).

Śpiączka afrykańska jest chorobą wywoływaną przez pierwotniaki Trypanosoma brucei gambiense i Trypanosoma brucei rhodesiense, w jej amerykańskiej odmianie przez Trypanosoma cruzi. Pasożyty te są jednokomórkowymi pierwotniakami, które mają złożony cykl życiowy i posiadają dwóch żywicieli, z których jednym jest człowiek. Świdrowce te butują we krwi człowieka, jednak w późnych etapach infekcji mogą zasiedlać także płyn mózgowo-rdzeniowy, i wywoływać tak zwaną śpiączkę. W organizmie żywiciela pośredniego i ostatecznego pasożyty przyjmują szereg postaci. Choroba ta prowadzi często do śmierci, choć jest możliwa do wyleczenia zwłaszcza w pierwszych etapach infekcji. Może ona zostać zwalczona środkami farmakologicznymi, jednak nie są one obojętne dla zdrowia człowieka, dlatego kluczową rolę odgrywa stosowanie środków zapobiegawczych, eliminujących znacznie ryzyko wystąpienia 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

Phenotypic plasticity in taxonomic traits of the tardigrade Diphascon higginsi BINDA, 1971 (Tardigrada: Eutardigrada: Hypsibiidae)

Niesporczaki (Tardigrada) to typ bezkręgowców zaliczanych do wylinkowców (Ecdysozoa). Zasiedlają one przede wszystkim środowisko wodne, przy czym żyją zarówno w wodach słodkich jak i słonych, oraz lądowe, gdzie żyją zwykle w środowisku o wysokiej wilgotności, jakiej dostarczają im mchy bądź porosty. Organizmy te cechują się wysoką odpornością na ekstremalne warunki środowiskowe, takie jak dehydratacja czy niskie i wysokie temperatury. Pozycja systematyczna niesporczaków jest stosunkowo niejasna. Typ ten obejmuje trzy gromady: Heterotardigrada, Mesotardigrada i Eutardigrada.W poniższej pracy skupiłam się na gatunku Diphascon higginsi BINDA, 1971, należącym do gromady Eutardigrada, który obejmuje przede wszystkim gatunki lądowe i słodkowodne. Celem serii eksperymentów opisanej w niniejszej pracy było oszacowanie plastyczności fenotypowej w morfometrycznych cechach ważnych taksonomicznych, względem temperatury i dostępności pożywienia. W początkowym etapie eksperymentu z jednej partenogenetycznej samicy wyprowadzono klonalny szczep D. higginsi, co umożliwiło zinterpretowanie zaobserwowanej zmienności jako plastyczności fenotypowej. W eksperymencie zostało wykorzystanych pięć zabiegów środowiskowych: stałe temperatury 8°C, 16°C, 20°C, temperatura fluktuująca (cyklicznie 8-16-20-16-8 °C) oraz zabieg z ograniczoną dostępnością pokarmu (w 16 °C). Łącznie uzyskano 540 osobników, z których uzyskano około 4300 pomiarów cech taksonomicznych.Plastyczność fenotypowa u w klonalnej populacji D. higginsi okazała się być znacząca, jednak bez istotnych różnic pomiędzy przeprowadzonymi zabiegami w średnich i zakresach rozmiarów zmierzonych struktur. Wyniki uzyskane w niniejszej pracy były eksperymentalnym testem dla zasadności przeprowadzania tradycyjnych analiz taksonomicznych z użyciem 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°C, 16°C, 20°C, a fluctuating temperature (cycles of 8-16-20-16-8 °C) and periodic starvation (at 16 °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 × 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 × 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. × 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. × 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. × 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 ciężkimi mają toksyczne działanie na rośliny, zwierzęta oraz człowieka. Metalofity, rośliny odporne na metale ciężkie, kolonizujące tereny metalonośne, są wykorzystywane do fitoremediacji, czyli oczyszczania gleb z metali ciężkich. Wykorzystanie roślinnych kultur komórkowych do badań nad toksycznością metali i tolerancją komórek na ich działanie jest stosunkowo nową techniką. W pracy zostały przedstawione możliwości wykorzystania roślinnych kultur zawiesinowych w badaniach nad wpływem metali ciężkich na metabolizm komórek oraz metody oszacowania ich toksycznego wpływu. Zaprezentowane zostały techniki otrzymywania kultur zawiesinowych, oceny żywotności komórek, akumulacji metali ciężkich w komórkach. W ocenie toksyczności metali stosuje się także badania nad programowaną śmiercią komórki (PCD), co pozwala oszacować reakcję komórek na ich wysokie stężenia. Zostały przedyskutowane mechanizmy tolerancji komórek na metale ciężkie. Kultury zawiesinowe są dobrym modelem do badań tolerancji na metale, ponieważ pozwalają zbadać ich wpływ na pojedyncze komórki w jednolitych, stałych 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—Discovering 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