The oral bioavailability of soil-borne risk elements for small terrestrial mammals: Microtus arvalis (Pallas, 1778) and Apodemus sylvaticus L. and its implication in environmental studies

The aims of this study were (i) to specify real risk elemetnt (RE) uptake by wild terresrial mammals (A. sylvaticus and M. arvalis), (ii) to describe RE distribution in critical organs such as the liver and kidney, and (iii) to determine potencial differences in RE toxicokinetics with regards to individual species or sex. Three groups of experimental animals were fed diets amended with soil and green biomass of hyperaccumulator Arabidopsis halleri with different RE levels. The contents of As, Cd, and Pb in the liver and kidneys of the animals reflected the element contents in the diet. Higher Cd and Pb accumulation ability was observed in A. sylvaticus compared to M. arvalis tissues, and an opposite pattern was recorded for As. Zn contents in tissues of both species remained unchanged, and total contents of Zn in the exposed animals even tended to decrease compared to the controls. Results of this study indicate a generally similar response of both species to elevated RE contents in the diet, confirming these wild rodents as suitable models for RE biomonitoring in ecosystems. However, our data highlights some distinction in As toxicokinetics in wood mice compared to that of field voles and a significantly higher accumulation of Pb and Cd in females. Therefore, factors of species and sex should not be overlooked if relevant data are to be obtained in environmental studies conducted on small terrestrial rodents.

Molecular cytogenetic analysis of a triploid population of the human broad tapeworm, Dibothriocephalus latus (Diphyllobothriidea)

The large-sized tapeworm Dibothriocephalus latus is known as the broad or fish-borne cestode of mammals that is capable to infect humans and cause diphyllobothriosis. Recently, molecular data on D. latus has been accumulating in the literature and a complete genome sequence has been published; however, little is known about the karyotype and chromosome architecture. In this study, an in-depth karyological analysis of 2 D. latus specimens was carried out. The plerocercoids originated from a perch caught in subalpine Lake Iseo (Italy) and the tapeworms were reared in hamsters. Both specimens contained cells with a highly variable number of chromosomes ranging from18 to 27. Nevertheless, the largest portion of mitotic figures (47%) showed a number corresponding to the triploid set, 3n = 27. Accordingly, the karyotype of the analyzed specimens consisted of 9 triplets of metacentric chromosomes. Fluorescence in situ hybridization (FISH) with the 18S rDNA probe clearly demonstrated the presence of 3 clusters of hybridization signals on the triplet of chromosome 7, thus confirming the triploid status of the specimens. FISH with a telomeric (TTAGGG)n probe confined hybridization signals exclusively to the terminal chromosomal regions, supporting the earlier findings that this repetitive motif is a conserved feature of tapeworm telomeres.

The response of soil nematode Caenorhabditis elegans on the sewage sludge-derived micropollutants

Sewage sludge application to soil is of great interest, due to required organic matter and the wide spectra of nutrients it provides. However, the presence of unpredictable content of emerging contaminants may turn this valuable raw material into a hazardous substance. In this study, three selected sewage sludges derived micropollutants from different origins; that is, one each under persistent organic pollutants (POPs), pharmaceuticals and personal care products (PPCPs) were considered. The effect of each micropollutant on the feeding activity of free-living soil nematode Caenorhabditis elegans was analysed. The analysis was performed in model soil solution using a larval feeding inhibition assay. The results showed no significant effects from selected POP-2,2',4,4',5-pentabromodiphenyl either and pharmaceutical-chlortetracycline on the feeding activity of tested nematodes. On the contrary, feeding activity was inhibited by PPCP-galaxolide (HHCB) with an effective concentration of 12.2 ± 2.2 mg.l-1. The calculated risk quotient for galaxolide (RQ = 0.14) demonstrated a medium ecological risk to the nematodes. Based on our findings, concentrations of micropollutants in sewage sludge treated soil pose negligible risk to feeding activity of soil nematode. However, the potential impact of musk compounds on free-living soil biota requires detailed evaluation in further research.

Mobility and bioaccessibility of risk elements in the area affected by the long-term opencast coal mining

The potential environmental hazards of risk elements in the area affected by the opencast coal mine and/or coal combustion for plants and animals was assessed by using a suite of laboratory bioaccessibility tests. The chosen sampling area was in the vicinity of the largest coal mine spoil in the Sokolov coal basin (Czech Republic). For an estimation of the oral bioaccessibility of the risk elements in soils, the physiologically based extraction tests were applied. Among the available methods for estimating the pulmonary bioaccessibility of elements, the Gamble's and Hatch's tests were chosen. The results showed elevated pseudo-total soil contents of As, Be, Cd, Cu, Pb, V, and Zn. Among these elements, only Cd showed substantial bioaccessibility for plants, as documented by the high Risk Assessment Code, reaching up to 47%, and the highest plant-availability, where the maximum Bioaccumulation Factor in plants reached up to 4.5. The simulated body fluids showed the highest bioaccessibility of Cd, but also substantial bioaccessible pools of As and Be, the elements frequently found at the brown coal mining and processing areas. For better understanding of the risk element bioaccessibility under the specific conditions, the released element pools should be related to the particular soil physicochemical parameters.

Variability of trace element distribution in Noccaea spp., Arabidopsis spp., and Thlaspi arvense leaves: the role of plant species and element accumulation ability

Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) was applied for the determination of Cd and Zn distributions within the leaves of Cd- and Zn-hyperaccumulating plants, Noccaea caerulescens, N. praecox, and Arabidopsis halleri, in contrast to nonaccumulator species, Thlaspi arvense and A. thaliana. The elemental mapping of the selected leaf area was accomplished via line scans with a 110-μm-diameter laser beam at a 37-μm s^-1 scan speed and repetition rate of 10 Hz. The lines were spaced 180 μm apart and ablated at an energy density of 2 J cm^-2. The elemental imaging clearly confirmed that Cd was predominantly distributed within the parenchyma of the T. arvense, whereas in the Noccaea spp. and A. halleri, the highest intensity Cd signal was observed in the veins of the leaves. For Zn, higher intensities were observed in the veins for all the plant species except for A. thaliana. Close relationships between Zn and Ca were identified for the Noccaea spp. leaves. These relationships were not confirmed for A. halleri. Significant correlations were also proved between the Cd and Zn distribution in A. halleri, but not for the Noccaea spp. For both T. arvense and A. thaliana, no relevant significant relationship for the interpretation of the results was observed. Thus, the LA-ICP-MS imaging is proved as a relevant technique for the description and understanding of the elements in hyperaccumulating or highly accumulating plant species, although its sensitivity for the natural element contents in nonaccumulator plant species is still insufficient.

Metabolic transformation and urinary excretion of selenium (Se) in rats fed a Se-enriched defatted rapeseed (Brassica napus, L.) diet

Se-enriched defatted rapeseed can be a suitable Se-supplement in diet of monogasters.

Efficacy and persistent activity of moxidectin against natural Muellerius capillaris infection in goats and pathological consequences of muelleriosis

The effect of moxidectin against natural Muellerius capillaris infection in goats was evaluated in this study. Long-acting moxidectin at a single dose of 1 mg kg(-1) body weight was administered to an entire flock (n=10) of goats. The individual faecal larval count reduction was applied as an indicator of treatment efficacy. A significant reduction (>98%) in larval counts was observed in all surveyed animals 14 days after drug administration. Moxidectin demonstrated persistent activity in this study; the mean faecal larval count reduction was 99.1% ± 1.8 on day 77 of the treatment. Macroscopic abnormalities and histological changes in the lungs of two infected goats were evident during the post-mortem examination. The pathological consequences of M. capillaris infection were observed even three months after parasite elimination. The results of this study indicate that moxidectin is a highly effective anthelmintic agent for the control of muelleriosis in goats. This drug provides animals with fifteen weeks of protections against M. capillaris reinfection.

Effects of age, sex, lactation and social dominance on faecal egg count patterns of gastrointestinal nematodes in farmed eland (Taurotragus oryx)

The eland is a large African antelope that can be bred in a temperate climate, under similar conditions and production systems as cattle. However, knowledge of parasites in farmed elands outside the area of their native habitat is still limited, and information concerning factors that influence these parasites is lacking. Therefore, faecal samples from an entire herd of elands, including calves and adult females and males, were examined monthly over a one year period. Almost 84% of the animals were found to be positive for gastrointestinal nematodes. Strongyle-type eggs were most frequently detected (prevalence 75%), followed by Capillaria sp., Nematodirus sp. and Trichuris sp. eggs. Following culturing eggs to infective larvae, Teladorsagia sp., Trichostrongylus sp., Nematodirus sp., Cooperia sp. and Oesophagostomum sp. were identified. Following necropsy of two calves that died during the study one abomasal nematode (Teladorsagia circumcincta), five small intestinal nematode species (Nematodirus helvetianus, N. spathiger, Cooperia oncophora, C. curticei and Capillaria bovis) and two large intestinal nematodes (Oesophagostomum venulosum and Trichuris ovis) were recovered. From these findings, it is evident that the eland harbours nematodes that are typical for domestic cattle and small ruminants. Morphological and morphometric analyses of recovered nematodes revealed that these parasites do not require any special morphological adaptation to establish infection in elands. The faecal output of strongyle-type and Nematodirus sp. eggs was seasonal, with the highest egg production taking place during spring and summer. Calves had higher faecal egg counts (for all the monitored nematode species) than adults did. Lactation in females was significantly (P<0.0001) associated with higher strongyle nematode egg shedding. Social dominance also affected faecal egg count patterns. The lower the hierarchical position among adults (regardless of sex), the higher the risk of nematode infection. This effect was evident for strongyles (P<0.0001) and Capillaria sp. nematodes (P=0.0065). The results of our study suggest that control measures applicable in domestic cattle and small ruminants might be similarly applicable for controlling gastrointestinal nematode infections in captive farmed elands.

The effect of Syphacia muris on nutrient digestibility in laboratory rats

This study was carried out to investigate how pinworm infection in rats affects nutrient digestibility in the hosts. Twenty-four male outbred Wistar rats were randomly divided into two groups of 12 rats each. The rats from the first group (GI) were kept in cages with bedding containing pinworm eggs, and the second (control) group (GII) were kept in a separate room in clean, uncontaminated filter-top cages. The animals were put into individual metabolic cages later. Metabolic trials lasted five days and records of animal weight, food ingestion, and faecal weight were taken daily. Based on laboratory analysis of the feed and faecal nutrient content, digestibility values were determined. On day 15 of the experiment, the animals were euthanized. Although Syphacia muris were found in all rats from the GI group, animals exhibited no clinical signs. In our experiment, S. muris infection reduced the overall digestibility of all measured nutrients (P < 0.01). The most significant differences in digestibility were observed in the case of crude fibre and mineral matter (P < 0.01).

Bioaccessibility versus bioavailability of essential (Cu, Fe, Mn, and Zn) and toxic (Pb) elements from phyto hyperaccumulator Pistia stratiotes: potential risk of dietary intake

Aquatic weeds are widely used as animal feed in developing countries. However, information about element bioavailability from these plants is lacking. A combination of an in vitro method [physiologically based extraction test (PBET)] and an in vivo feeding trial was used in this study to investigate potential element bioaccessibility and estimated bioavailability of Pistia stratiotes (PS). Cu, Fe, Mn, Zn, and Pb concentrations in PS biomass, artificial gastrointestinal fluids, and rat tissues were determined using atomic absorption spectrometry with electrothermal atomization and inductively coupled plasma-atomic emission spectrometry. PS exhibited elevated Fe, Mn, and Pb levels. The PBET revealed high bioaccessibility of all monitored elements from PS biomass. The results of the in vivo trial were inconsistent with those of the PBET, because animals fed PS exhibited low levels of essential elements in the tissues. The consumption of a PS-supplemented diet significantly decreased total Fe levels and increased the total level of accumulation of Pb in exposed animals. Significantly reduced amounts of essential elements in the intestinal walls indicated a potential disruption in nutrient gastrointestinal absorption in animals fed PS.

Effect of lead in water on the absorption of copper, iron, manganese and zinc by sheep (Ovis aries) infected with sheep tapeworm (Moniezia expansa)

The sheep tapeworm (Moniezia expansa) and its host Ovis aries were analyzed by inductively coupled plasma optical emission spectrometry (ICP-OES) for their copper, iron, manganese, zinc and lead levels. Element concentrations in cestode parasites were compared to those in various organs (liver, kidney, and muscle) of sheep. Tapeworms in the small intestine of sheep that were administered 2g of Pb(CH(3)COO)(2) per os daily (7 days) had significantly higher lead concentrations than sheep tissues. Cu levels significantly increased after Pb administration in sheep muscle and sheep tapeworms. Contrarily, Zn content significantly decreased in sheep muscle, but significantly increased in sheep tapeworms. However, Mn content significantly decreased after Pb administration in sheep tapeworms. Furthermore, Fe content significantly decreased after Pb administration in sheep liver and kidneys.

Concentrations of Zn, Mn, Cu and Cd in different tissues of perch (Perca fluviatilis) and in perch intestinal parasite (Acanthocephalus lucii) from the stream near Prague (Czech Republic)

We monitored concentrations of Cd, Cu, Mn and Zn in acantocephalan parasites (Acanthocephalus lucii) and its final host (Perca fluviatilis). The concentrations in parasites were found to be significantly higher than those found in the muscle, gonads and liver of fish host. The bioaccumulation factor values (BF=C(parasite)/C(host muscle)) were 194, 24.4, 2.2 and 4.7 for Cd, Cu, Mn and Zn, respectively. This suggests a benefit for the host due to the high accumulation of toxic cadmium.