Aquarium hitchhikers: attached commensals imported with freshwater shrimps via the pet trade

The keeping of home aquaria is one of the most popular hobbies globally. In contrast to the ornamental fish trade, decapod crustaceans such as shrimps, crayfish and crabs are relatively new to the pet trade. Nevertheless, the popularity of ornamental shrimp in freshwater aquaria has rapidly increased in recent years. Indonesia is one of the leading producers and exporters of ornamental aquatic animals globally and the Czech Republic is a gateway for these animals into the European Union territory. The pathway for introductions of organisms unintentionally moved in association with ornamental shrimps via the international trade has to date not been evaluated. We examined a small number of shrimps imported from Indonesia into the Czech Republic in May 2015 and found large numbers of the protozoan Vorticella sp., one species of scutariellid temnocephalidan (Caridinicola sp.), and one species of bdelloid rotifer, associated with two species of atyid shrimps, indicating an invasion risk from fauna carried unintentionally by this vector. Although our observations were limited in scale, we estimate the total number of commensal fauna imported into the Czech Republic with ornamental shrimps via the pet trade to be in the order of hundreds of thousands per month. As attached organisms can directly or indirectly cause diseases in certain species of decapod crustaceans, we recommend five steps to reduce risks of introduction of “hitchhikers” to aquaria and wildlife.     

Selenium protects the immature rat heart against ischemia/reperfusion injury

The aim of the study was to find out whether administration of selenium (Se) will protect the immature heart against ischemia/reperfusion. The control pregnant rats were fed laboratory diet (0.237 mg Se/kg diet); experimental rats received 2 ppm Na₂SeO₃ in the drinking water from the first day of pregnancy until day 10 post partum. The concentration of Se in the serum and heart tissue was determined by activation analysis, the serum concentration of NO by chemiluminescence, cardiac concentration of lipofuscin-like pigment by fluorescence analysis. The 10 day-old hearts were perfused (Langendorff); recovery of developed force (DF) was measured after 40 min of global ischemia. In acute experiments, 10 day-old hearts were perfused with selenium (75 nmol/l) before or after global ischemia. Sensitivity to isoproterenol (ISO, pD₅₀) was assessed as a response of DF to increasing cumulative dose. Se supplementation elevated serum concentration of Se by 16%. Se increased ischemic tolerance (recovery of DF, 32.28 ± 2.37 vs. 41.82 ± 2.91%, P < 0.05). Similar results were obtained after acute administration of Se during post-ischemic reperfusion (32.28 ± 2.37 vs. 49.73 ± 4.40%, P < 0.01). The pre-ischemic treatment, however, attenuated the recovery (23.08 ± 3.04 vs. 32.28 ± 2.37%, P < 0.05). Moreover, Se supplementation increased the sensitivity to the inotropic effect of ISO, decreased cardiac concentration of lipofuscin-like pigment and serum concentration of NO. Our results suggest that Se protects the immature heart against ischemia/reperfusion injury. It seems therefore, that ROS may affect the function of the neonatal heart, similarly as in adults.     

Field measurement of soil water repellency and its impact on water flow under different vegetation

Numerous recent laboratory studies have shown that vegetation can influence soil water flow by inducing very low levels of water repellency. In this study we extended on this previous research by developing a field-based test using a miniature infiltrometer to assess low levels of water repellency from physically based measurements of liquid flow in soil. The field-based test was verified through a simple laboratory experiment and then applied to determine the impact of vegetation and antecedent soil water content. The soil hydraulic properties determined were hydraulic conductivity, sorptivity, as well as the persistence and index of water repellency. Tests were conducted following a dry spell and wet spell on (1) forest soil (0 cm depth), (2) glade soil (0 cm depth) and (3) glade soil (50 cm depth). It was found that both the persistence and index of water repellency, R, decreased in the order as follows: forest soil > glade soil (0 cm) > glade soil (50 cm) for both dry and wet spell. The range of values of R was 0.28 (wettable) to 360 (highly water repellent), which affected hydraulic conductivity k _r(−2 cm). R increased and hence k _r(−2 cm) decreased in the order: forest soil < glade soil (0 cm) < glade soil (50 cm) for both the dry and wet spell. There were clear interactions between vegetation and changes to water flow caused by presence of repellency. Presented at the International Conference on Biohydrology, Prague, Czech Republic, 20–22 September 2006.     

High bromide intake affects the accumulation of iodide in the rat thyroid and skin

The effect of a high bromide intake on the kinetics of iodide uptake and elimination in the thyroid and skin of adult male rats was studied. In rats fed a diet with sufficient iodine supply (>25 μg I/d), the iodide accumulation in the skin predominated during the first hours after ¹³¹I -iodide application. From this organ, radioiodide was gradually transferred into the thyroid. A high bromide intake (>150 mg Br⁻/d) in these animals led to a marked decrease in iodide accumulation, especially by the thyroid, because of an increase in iodide elimination both from the thyroid and from the skin. In rats kept under the conditions of iodine deficiency (<1 μ I/d), the iodide accumulation in the thyroid, but not in the skin, was markedly increased as a result of a thyrotropic stimulation. The effect of a high bromide intake (>100 mg Br⁻/d) in these animals was particularly pronounced because the rates of iodide elimination were most accelerated both from their thyroid and from their skin. Presented in part at the 20th Workshop on Macro and Trace Elements held in Jena (Germany) on December 1–2, 2000.     

New and little-known species of Rhagidiidae from talus ecosystems, in the Czech Republic and Austria

Two new species of mites, Foveacheles (Proxistella) simulata n.sp. and Rhagidia longiseta n.sp., are described, and the little-known Foveacheles (Proxistella) terricola (C. L. Koch) is redescribed. All species were found inhabiting underground spaces in talus formations in the Czech Republic and Austria.     

Clustered ergot alkaloids modulate cell-mediated cytotoxicity.

Dimers of agroclavine (1) and terguride (2), as well as a series of terguride oligomers, for example trimers (5, 6), tetramer (7), hexamer (8) and functionalized tergurides for further complex clustering were synthesized. Terguride oligomers were screened for their direct cellular toxicity on lymphoma cell lines in vitro and for their immunomodulating activities, represented by the natural killer (NK) cell-mediated cytotoxicity, as the most sensitive screening marker during immune responses. Dimers linked via aromatic spacer showed a high toxicity (1 microM) to lymphoma cells, which was not detected in other derivatives. In vitro and ex vivo experiments performed on mouse spleen lymphocytes in the presence of terguride oligomers demonstrated an immunosuppressive effect of dimers with aromatic spacer (4c-d) and NK cell stimulatory effect of terguride hexamer (8) and trimer with aliphatic spacer (5c). There is a considerable evidence that indolic part of molecule contributes to immunosuppressive action of terguride, which is potentiated in dimers carrying aromatic linker. This effect can be reversed by higher oligomerization of the respective alkaloids.     

Calcium ion uptake by Methanobacterium thermoautotrophicum: Evidence for a carrier-mediated uptake system

Abstract Cell suspensions of Methanobacterium thermoautotrophicum took up ⁴⁵Ca²⁺ in a temperature-dependent, Ca²⁺-saturable and Co²⁺-sensitive process. The accumulation of ⁴⁵Ca²⁺ was lower in the cells energized by CO₂+ H₂ than in those under non-energized conditions. The accumulated Ca²⁺ were, in part, released by the divalent cations ionophore A23187 in the presence of EGTA while the uptake of Ca²⁺ was accelerated by the addition of A23187 to the medium containing Ca²⁺. The results indicate the presence of a carrier-mediated Ca²⁺ uptake in the Methanobacterium thermoautotrophicum membrane which is compensated by an energy-dependent and outward-directed Ca²⁺ transport.     

Annual Cycle of Planktothrix agardhii (Gom.) Anagn. & Kom. Nature Population

Changes in abundance, biovolume and morphology of Planktothrix agardhii in a natural population were followed over one year period in shallow fishpond Bílá Lhota (Central Moravia, Czech Republic). The selected environmental parameters (pH, oxygen, temperature, conductivity, nutrients, light) were measured at the surface and at the bottom of the fishpond, together with the Planktothrix abundances and filament morphology – filament length, width, shape, aerotopes (gas vacuoles) formation. The annual cycle of P. agardhii in this hypertrophic fishpond starts in March with the germination of hormogonia and the growth of overwintered filaments. The filament length quickly increases to a maximum length in April. The following summer period can be characterized by filament shortening and by changes in the aerotopes shape. On the other hand the abundance and biomass of P. agardhii is increasing until the maximum in August. Further shortening of filaments, loss of aerotopes and hormogoniae formation is typical for the autumn (October) with the average temperature of 9.4 °C. The population overwinters near the pond bottom in the form of hormogonia (60%) and filaments (40%). (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)