Effect of Cephalosporin Antibiotics on the Activity of Yoghurt Cultures.

The presence of antibiotics in milk is a significant problem affecting the technological safety of dairy products. The aim of the study was to determine the sensitivity of yoghurt cultures to residual levels of selected cephalosporin antibiotics (cephalexin, cefoperazone, cefquinome, cefazolin, and ceftiofur). Five yoghurt cultures were selected containing strains of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus. Artificially fortified milk samples (whole pasteurized milk; 85 °C; 3−5 s) with cephalosporins at a concentration of the maximum residue limit were used to evaluate the sensitivity of the yoghurt cultures by monitoring the pH, titratable acidity, and the concentration of selected organic acids (lactic, pyruvic, citric, acetic, orotic, oxalic, formic, uric, and succinic acids) at the end of fermentation (43 °C; 4−5.5 h; pH ≤ 4.6). The titratable acidity was determined by the Soxhlet−Henkel method and the organic acid concentration was monitored by reversed-phase HPLC. Ceftiofur had the greatest effect on the yoghurt culture activity, with a statistically highly significant effect (p < 0.05) on the pH, titratable acidity, and the content of lactic, pyruvic, and acetic acids in all cultures. Other cephalosporins also showed an inhibitory effect on yoghurt metabolism as seen by the evaluation of the lactic and pyruvic acid concentrations.

Study of the influence of platinum, palladium and rhodium on duckweed (Lemna minor).

OBJECTIVES: Road traffic pollutants and the residues of cytostatics that are widely used in anti-cancer therapy are a significant sources of platinum group elements (PGE; Pt, Pd and Rh) in environment. These metals can migrate into sewage and thus pollute surface waters. The purpose of our study was to evaluate the effect of PtCl4 on the antioxidant and enzymatic activity of duckweed (Lemna minor), a bioindicator of the aquatic environment. METHODS: The study was performed using a 7-day conventional test based on the OECD 221 (CSN EN ISO 20079)--Lemna sp. Growth Inhibition Test. We also conducted a microbiotest to analyse the effects of PtC4, PdCl2 and RhCl3 on the morphology and vegetative growth of colonies of this plant and compared their inhibitory effects during the microbiotest. RESULTS: We observed inhibition of colony growth and clear morphological changes. Antioxidant and enzymatic activities increased with platinum doses increased. The 168hEC50 of PtCl4 was 12.16 µM (95% confidence interval = 9.88-14.44) and the 168hEC50 of PdCl2 was 50.39 (95% confidence interval = 23.83-76.96). The greatest inhibition of growth by RhCl3 was observed at 25 µM. CONCLUSIONS: The obtained results suggest that L. minor phytotoxicity tests should be widely used in the biomonitoring.

Impact of platinum group elements on the soil invertebrate Enchytraeus crypticus.

OBJECTIVES: The platinum group elements (PGE) platinum (Pt), palladium (Pd), and rhodium (Rh) are used in automobile catalytic converters, from which they have been emitted into the environment to an increasing degree over the last 20 years. Despite the bioavailability of these metals to plants and animals, studies determining the effects of PGE on organisms are extremely rare. Enchytraeids are ecologically relevant soil organisms, due to their activity in decomposition and bioturbation in many soil types worldwide. DESIGN: The experiments were carried out as described in the OECD Guideline 220 [CSN EN ISO 16387--Soil quality--Effects of pollutants on Enchytraeidae (Enchytraeus sp.)--Determination of effects on reproduction]. The reproductive effects of platinum (PtCl4), palladium (PdCl2) and rhodium (RhCl3) were examined. The concentrations of PGE tested were as follows: 5, 10, 25, 50 and 100 µmol x L(-1) PdCl2; 50, 100, 150, 200 and 250 µmol x L-1 PtCl4/RhCl3. The EC50 (medium effective concentration) was determined after 28 days of exposure. The inhibition of the reproduction of PGE-exposed enchytraeids was compared against controls. RESULTS: Values of 28dEC50 of PtCl4, PdCl2 and RhCl3 amounted to 161.9 µmol x L(-1), 70.0 µmol x L(-1) and 246.6 µmol x L(-1), respectively. We can confirm that the relative order of toxicities is Pd (II) >Pt(IV) >>Rh(III). CONCLUSION: To the best of our knowledge, this is the first study to use Enchytraeus crypticus as an indicator species to assess the risk of soil contamination by platinum, palladium and rhodium. Results of this study contribute important data on the ecotoxicity of a rarely studied elements.

Impact of platinum group elements on the soil invertebrate Folsomia candida.

OBJECTIVES: Trace concentrations of the platinum group elements (PGE; Pt, Pd and Rh) are nowadays an irreplaceable part of environmental analysis and assessment. These rare elements are used as effective substances in automotive catalysts to reduce pollution by emissions originating from fuel combustion. Due to their harmful potential, it is necessary to monitor their content and behaviour in different samples. Effect assessment using ecotoxicological bioassays with organisms at different trophic levels can provide valuable pieces of information on the risk of chemical substances in the ecosystem. DESIGN: The experiments were carried out as described in the OECD Guideline 232 [CSN ISO 11267 - Soil quality - Inhibition of reproduction of Collembola (Folsomia candida) by soil pollutants]. The reproductive effects of palladium (PdCl2) and rhodium (RhCl3) were examined. Concentrations of PGE tested were as follows: 5, 10, 25, 50 and 100 µmol.L-1. The EC50 (medium effective concentration) was determined after 28 days of exposure. Inhibition of reproduction of PGE-exposed collembolans was compared against controls. RESULTS: Values of 28dEC50 of PdCl2 and RhCl3 amounted to 21.0 µmol.L-1 and 266.22 µmol.L-1, respectively. We can confirm that the relative order of toxicities is Pd (II) > Pt(IV) >> Rh(III). CONCLUSION: To the best of our knowledge, this is the first study to use Folsomia candida as an indicator species to assess the risk of soil contamination by palladium and rhodium. However, more toxicity data for various species are needed to evaluate the environmental risks of PGEs in soils.

Lead toxicosis of captive vultures: case description and responses to chelation therapy.

BACKGROUND: Lead, a serious threat for raptors, can hamper the success of their conservation. This study reports on experience with accidental lead intoxication and responses to chelation therapy in captive Cinereous (Aegypius monachus) and Egyptian (Neophron percnopterus) Vultures. RESULTS: Soil contamination by lead-based paint sanded off the steel aviary resulted in poisoning of eight Cinereous and two Egyptian Vultures. A male Egyptian Vulture developed signs of apathy, polydipsia, polyuria, regurgitation, and stupor, and died on the next day. Liver, kidney and blood lead concentrations were 12.2, 8.16 and 2.66 µg/g, respectively. Laboratory analyses confirmed severe liver and kidney damage and anaemia. Blood Pb levels of Pb-exposed Cinereous Vultures were 1.571 ± 0.510 µg/g shortly after intoxication, decreased to 0.530 ± 0.165 µg/g without any therapy in a month and to 0.254 ± 0.097 µg/g one month after CaNa(2)EDTA administration. Eight months later, blood lead levels decreased to close to the background of the control group. Blood parameters of healthy Pb-non-exposed Cinereous Vultures were compared with those of the exposed group prior to and after chelation therapy. Iron levels in the lead-exposed pre-treatment birds significantly decreased after chelation. Haematocrit levels in Pb-exposed birds were significantly lower than those of the controls and improved one month after chelation. Creatine kinase was higher in pre-treatment birds than in the controls but normalised after therapy. Alkaline phosphatase increased after chelation. A marked increase in the level of lipid peroxidation measured as thiobarbituric acid reactive species was demonstrated in birds both prior to and after chelation. The ferric reducing antioxidant power was significantly lower in pre-treatment vultures and returned to normal following chelation therapy. Blood metallothionein levels in lead-exposed birds were higher than in controls. Reduced glutathione dropped after CaNa(2)EDTA therapy, while oxidised glutathione was significantly lower in both pre- and post-treatment birds. A chick in an egg produced by a Cinereous Vulture female two months after lead toxicosis died on day 40 of artificial incubation. Lead concentrations in foetal tissues were consistent with levels causing avian mortality. CONCLUSIONS: The reported blood parameters and reproduction impairment in captive birds may have implications for professionals dealing with lead exposure in wild birds.

Comparison of the effect of platinum on producers in aquatic environment.

OBJECTIVES: An enhanced worldwide application of platinum group elements (PGE), in particular platinum, has been observed during recent decades. An increased concentration of PGE was determined in collected samples of great amount of aqueous ecosystems.The aim was to compare phytotoxic effect of platinum (PtCl4) by performing two different bioassays on green algae Pseudokirchneriella subcapitata and macrophyte duckweed, Lemna minor. MEDTHODS: The algal experiment (Pseudokichneriella subcapitata) followed OECD 201, the concentration row for PtCl4 was: 0.05; 0.01; 0.25; 0.5; 1 µM. The duckweed (Lemna minor) experiment was conducted according to OECD 221, employed PtCl4 concentrations were: 5; 10; 25; 50; 100 µM. Plants were cultivated as a microbiotest, using micro-volumes. RESULTS: The results of the algal test showed significant growth inhibition of the final biomass. The values of 72hEC5(µ), 72hEC10(µ), 72hEC20(µ) counted on a basis of average specific growth rate (µ) were 0.31 µM, 0.58 µM and 1.12 µM of PtCl4, respectively. The values, obtained on a basis of the area under the growth curves (A), were 0.04 µM (72hEC5(A)), 0.24 µM (72hEC10(A)) and 0.64 µM (72hEC20(A)). The experiment with duckweed showed 50% of growth inhibition and the values of 168hEC50(µ) were 19.55 µM and 168hEC50(A) 13.63 µM of PtCl4. CONCLUSION: The fronds of duckweed showed strong adverse effect of platinum influence (chlorosis, necrosis). The algal test and the estimation of 72hEC5(A) appears to be the most sensitive.

Impact of platinum on the soil invertebrate Folsomia candida.

OBJECTIVES: Regarding the environmental pollution, platinum group elements (PGE) are in the centre of interest of current research. These rare elements are used as effective substances in automotive catalysts to reduce pollution by emissions originating from fuel combustion. Due to their harmful potential, it is necessary to monitor their content and behaviour in different samples. Comprehensive studies on PGE behaviour and effects are still lacking. Their distribution in the food chain and data on bioaccumulation has not been described so far. METHODS: We focused on reproductive effects of platinum (PtCl4), in particular. Our study is based on a collembolan laboratory breed, test optimalization and validation according to the OECD 232 standards [CSN ISO 11267 - Soil quality - Inhibition of reproduction of Collembola (Folsomia candida) by soil pollutants]. The concentrations of PtCl4 tested were as follows: 5, 10, 25, 50 and 100 µM. The EC50 was determined after 28 days of testing. RESULTS: The results were evaluated using the inhibition of reproduction compared with controls. The EC50 was determined after the 28-day test. The value of 28dEC50 of the boric acid test was estimated at 120 mg/kg and the measured 28dEC50 of PtCl4 was 200.4 µM. CONCLUSION: The presented data can be considered as a step forward in the assessment of the potential risk of platinum in the terrestrial environment. However, more toxicity data for various species are needed to evaluate the environmental risk of platinum in soils.