Monitoring Metal Speciation in The rivers Meuse and Rhine Using DGT

Although a number of metal speciation methods are nowadays available, most water quality regulations are based on total metal concentrations. One of the main reasons for the ignorance of speciation is the lack of methods with potentiality for monitoring. Conditions that have to be met by such speciation methods are: simple performance, robust and sufficiently accurate. In this study the potential for monitoring purposes of Diffusive Gradients in Thin films (DGT) is investigated as part of a European project for sensor development for routine prediction of metal biouptake in natural waters. Performance characteristics of DGT have been assessed in experiments under controlled laboratory conditions and during in situ application over 4–9 months under different hydrological conditions in the rivers Meuse and Rhine. Results have been worked out for Cu, Ni and Pb. The study shows that DGT has sufficient potential as a robust tool in routine monitoring to observe trends in water quality. However, it appears that during in situ application of DGT the measurement uncertainty of the results is much larger than under laboratory conditions. The increase in measurement uncertainties will partially be due to uncertainties in some as constant considered factors in the calculation of the DGT concentration. For Cu and Ni, the average values for the reproducibility in the rivers Meuse and Rhine appeared to be 28% and 17%, respectively, whereas under laboratory conditions the reproducibilities for both metals were better than 10%. In the speciation of Cu, Ni and Pb in the rivers Meuse and Rhine, the labile fraction, determined using DGT, decreased in the series Ni, Cu, Pb. The ratio of the non-labile and labile fractions of the metals appeared to decrease with increasing content of Dissolved Organic Carbon (DOC).     

Divergent cytokine responses of macrophages to Mycobacterium avium subsp. paratuberculosis strains of Types II and III in a standardized in vitro model

Based on epidemiological and clinical observations, different strains of Mycobacterium avium subsp. paratuberculosis (MAP) are suspected to significantly differ in their virulence for ruminants. In the pathogenesis of paratuberculosis, macrophages represent the principal target cell for MAP. In order to judge the ability of different MAP-genotypes to modulate macrophage responses, the cytokine responses of the monocyte cell line THP-1 were studied after challenge with three different MAP strains under standardized conditions. The bovine field isolate J1961 (major Type II) and the ovine field isolate JIII-86 (Type III) were compared with the laboratory adapted reference strain ATCC 19698 (Type II). Strains were shown by three different typing methods (IS900-RFLP-, MIRU-VNTR-, and SSR-analysis) to substantially differ in several genotypic features. Macrophage function was assessed by quantifying mRNA of the cytokines TNF-α, IL-1?, and IL-10 by quantitative RT-PCR. Secreted TNF-α protein was measured by a cytotoxicity test, IL-1? and IL-10 using ELISA tests. The three MAP strains of various genotypes differ in their effect on human macrophages depending on challenge dose and infection time. These differences concerned both the mRNA level and secreted protein amounts of proinflammatory cytokines TNF-α, IL-1β and anti-inflammatory cytokine IL-10. Type III strain produced less IL-10 and IL-1β mRNA and protein but more TNF-α protein at 2h than the Type II strains. In summary, our results support the hypothesis that strain characteristics might have relevance for the host response towards MAP and, consequently, for the pathogenesis of paratuberculosis.     

Detection of Encephalitozoon cuniculi in the feline cataractous lens

Purpose Identification of Encephalitozoon cuniculi (E. cuniculi) as a possible causative agent for cataracts and uveitis in cats. Methods Within a 12‐month study period, cats that were presented with focal anterior cortical or mature cataract and secondary uveitis underwent a complete ophthalmic examination, complete blood count, serum biochemistry, serologic tests for E. cuniculi and tests for feline immunodeficiency virus (FIV), feline infectious peritonitis (FIP), feline leukemia virus (FeLV) and Toxoplasma gondii (T. gondii). PCR for DNA detection of E. cuniculi and T. gondii as well as cytologic examination of aqueous humor after paracentesis and phacoemulsified lens material were also performed. In addition histopathologic examination of the resected anterior lens capsule and attached lens epithelial cells was performed. Serologic testing for antibodies against E. cuniculi was also performed in 100 ophthalmologically healthy cats. Results Eleven (19 eyes) European shorthair cats with a median age of 3.5 years were included. Nine of 11 cats had bilateral cataracts, with 12/19 eyes having focal anterior cortical cataracts and 7/19 eyes having mature cataracts. In 14/19 eyes anterior uveitis was present. All cats had a positive antibody titer (1:80–1:10 000) for E. cuniculi. Encephalitozoon cuniculi DNA was detected by PCR and sequencing in 18/19 lenses and in 10/19 aqueous samples. Five tentative positive results were detected by cytologic examination. Spores were detected in 15/19 samples of lens material with histopathologic staining. Only 2/100 ophthalmologically healthy cats showed a positive antibody titer for E. cuniculi. Conclusion Encephalitozoon cuniculi is a cause of focal anterior cortical cataract and anterior uveitis in cats.     

Genetic diversity of Hungarian canine distemper virus strains

To achieve proper diagnosis of dogs based on acute clinical symptoms and poorly preserved field samples taken from animals that died due to canine distemper (CD), a new differential diagnostic test has been developed based on polymerase chain reaction (PCR). In this study, more than 150 samples collected from dogs showing respiratory, gastrointestinal and neurological signs suggesting canine distemper virus (CDV) infection were examined. The samples consisted of urine, blood and nasal swabs collected from clinically ill patients, sent to our laboratory by clinicians from various veterinary clinics throughout Hungary. Various organs collected during the necropsy of dogs with pathological changes that suggested CDV infection were also included. Three distinct PCRs were designed. For diagnostic purposes, a primer pair specific to a 409 bases-long segment within the conservative part of the large polymerase region (L) of the CDV genome was designed. Using this test, out of the 150 analyzed samples, 46 (30.66%) proved to be positive for CDV, indicating that CDV still represents a high risk to the canine population in Hungary. For the phylogenetical analysis, a primer pair that completely encompasses the hemagglutinin (H) gene of the CDV genome was designed. The amplicons of this region were sequenced in both directions using the appropriate primers. Our results indicate that several different CDV genotypes are currently present in Hungary. Nine of the analyzed Hungarian strains turned out to belong to the so-called Arctic group of CDVs, and were most closely related to non-European strains from North America, China and Greenland, as well as to the phocine distemper virus 2 (PDV-2) isolated from Baikal seals (Phoca sibirica). One of the Hungarian strains showed high similarity to other European isolates from Denmark, Germany, Italy and Turkey, as well as to other isolates from geographically more distant regions, such as the USA. Three Hungarian strains seem to join a new cluster that is formed by only a couple of strains, one isolated from a mink in Denmark, and another from a dog in North America. Using a third set of primers, a restriction fragment length polymorphism (RFLP) assay has also been designed for the fast and reliable differentiation of the wild-type CDVs from the vaccine strains.     

Crystal structure of a photolyase bound to a CPD-like DNA lesion after in situ repair

DNA photolyases use light energy to repair DNA that comprises ultraviolet-induced lesions such as the cis-syn cyclobutane pyrimidine dimers (CPDs). Here we report the crystal structure of a DNA photolyase bound to duplex DNA that is bent by 50 degrees and comprises a synthetic CPD lesion. This CPD lesion is flipped into the active site and split there into two thymines by synchrotron radiation at 100 K. Although photolyases catalyze blue light-driven CPD cleavage only above 200 K, this structure apparently mimics a structural substate during light-driven DNA repair in which back-flipping of the thymines into duplex DNA has not yet taken place.     

Type of organic carbon amendment influences pH changes in acid sulfate soils in flooded and dry conditions

Purpose

Acid sulfate soils (ASS) are common in wetlands and can pose an environmental threat when they dry because oxidation of pyrite may cause strong acidification. Addition of organic matter can stimulate sulfate reduction during wet periods and minimize acidification during dry periods. However, the effect of the organic amendment may depend on its composition.

Materials and methods

Three wetland acid sulfate (sulfuric, hypersulfidic, and hyposulfidic) soils collected from different depth in one profile were used. The soils, unamended or amended with 10 g C kg^?1 as glucose, wheat straw, pea straw, or Phragmites litter, were incubated for 18 weeks under flooded conditions (“wet period”) followed by 10 weeks during which the soils were maintained at 100 % of maximum water-holding capacity (“dry period”).

Results and discussion

During the wet period, the pH decreased in the control and with glucose to pH 3–4, but increased or was maintained in residue-amended soils (pH at the end of the wet period about 7). In the dry period, the pH of the control and glucose-amended soils remained low, whereas the pH in residue-amended soils decreased. However, at end of the dry period, the pH was higher in residue-amended soils than in the control or glucose-amended soils, particularly with pea straw (C/N 50).

Conclusions

Amendment of acid sulfate soils with plant residues (particularly those with low to moderate C/N ratio) can stimulate pH increase during flooding and reduce acidification under oxidizing conditions.

     

C. Veröffentlichungen aus dem Institut 1989

Das Institut Im Jahre 1989

C. Veröffentlichungen aus dem Institut 1989     

Salt-affected soils,reclamation, carbon dynamics,and biochar: a review

Purpose

This paper reviews chemical, physical, and biological problems of salt-affected soils and different reclamation methods applied to rehabilitate these soils.

Methods

Methods to increase C stocks in these lands are discussed with a focus on biochar application as a potential new approach to not only to increase the C content but also to improve soil properties. Gaps in research knowledge in this field are then identified.

Results

Given the concern on the continued worldwide expansion of salt-affected lands and the focus on C sequestration processes, this review has evaluated current knowledge on salt-affected soils and their remediation with organic materials and plants. The review of the published literature has highlighted important gaps in knowledge, which limit our current understanding of rehabilitation of salt-affected soils with organic amendments specially biochar and the associated carbon dynamic. Knowledge about application of biochar in salt-affected soils is scant, and to date, most studies have evaluated biochar use only in nonsalt-affected soils.