Multi-Level System to Assess Toxicity in Water Distribution Plants

The toxicity of water samples from water distribution plants needs to be investigated further. Indeed, studies on the pro-oxidant effects driven by tap water are very limited. In this study, the water quality, pro-oxidant effects, and potential health risks driven by exposure to groundwater samples from two water plants (sites A and B) located in Northwestern Italy were investigated in a multi-level system. Physicochemical parameters and the absence of pathogens, cyanotoxins, and endocrine active substances indicated a good water quality for both sites. The 25 metals analyzed were found under the limit of quantification or compliant with the maximum limits set by national legislation. Water samples were concentrated by the solid-phase extraction system in order to assess the aquatic toxicity on Epithelioma papulosum cyprini (EPC) cell line. Levels of superoxide dismutase, catalase, glutathione peroxidase, glutathione S-transferase, and glutathione reductase were evaluated through the Integrated Biomarkers Response (IBRv2) index. EPC cell line was found a sensible model for assessing the antioxidant responses driven by both water concentrates. A similar antioxidant response was shown by plots and IBRv2 suggesting a muted risk for the two sampling sites.

RT-QuIC detection of pathological prion protein in subclinical goats following experimental oral transmission of L-type BSE

Objective

The spread of bovine spongiform encephalopathy (BSE) agent to small ruminants is still a major issue in the surveillance of transmissible spongiform encephalopathies (TSEs). L-type bovine spongiform encephalopathy (L-BSE) is an atypical form of BSE with an unknown zoonotic potential that is transmissible to cattle and small ruminants. Our current knowledge of bovine atypical prion strains in sheep and goat relies only on experimental transmission studies by intracranial inoculation. To assess oral susceptibility of goats to L-BSE, we orally inoculated five goats with cattle L-BSE brain homogenates and investigated pathogenic prion protein (PrP^sc) distribution by an ultrasensitive in vitro conversion assay known as Real-Time Quaking Induced Conversion (RT-QuIC).

Results

Despite a prolonged observation period of 80 months, all these animals and the uninfected controls did not develop clinical signs referable to TSEs and tested negative by standard diagnostics. Otherwise, RT-QuIC analysis showed seeding activity in five out of five examined brain samples. PrP^sc accumulation was also detected in spinal cord and lymphoreticular system. These results indicate that caprine species are susceptible to L-BSE by oral transmission and that ultrasensitive prion tests deserve consideration to improve the potential of current surveillance systems against otherwise undetectable forms of animal prion infections.

Gene-targeted embryonic stem cells: real-time PCR assay for estimation of the number of neomycin selection cassettes

In the preparation of transgenic murine ES cells it is important to verify the construct has a single insertion, because an ectopic neomycin phosphortransferase positive selection cassette (NEO) may cause a position effect. During a recent work, where a knockin SCA28 mouse was prepared, we developed two assays based on Real-Time PCR using both SYBR Green and specific minor groove binder (MGB) probes to evaluate the copies of NEO using the comparative delta-delta Ct method versus the Rpp30 reference gene.

We compared the results from Southern blot, routinely used to quantify NEO copies, with the two Real-Time PCR assays. Twenty-two clones containing the single NEO copy showed values of 0.98 ± 0.24 (mean ± 2 S.D.), and were clearly distinguishable from clones with two or more NEO copies.

This method was found to be useful, easy, sensitive and fast and could substitute for the widely used, but laborious Southern blot method.

Heme controls ferroportin1 (FPN1) transcription involving Bach1, Nrf2 and a MARE/ARE sequence motif at position -7007 of the FPN1 promoter

BACKGROUND

Macrophages of the reticuloendothelial system play a key role in recycling iron from hemoglobin of senescent or damaged erythrocytes. Heme oxygenase 1 degrades the heme moiety and releases inorganic iron that is stored in ferritin or exported to the plasma via the iron export protein ferroportin. In the plasma, iron binds to transferrin and is made available for de novo red cell synthesis. The aim of this study was to gain insight into the regulatory mechanisms that control the transcriptional response of iron export protein ferroportin to hemoglobin in macrophages.

DESIGN AND METHODS

Iron export protein ferroportin mRNA expression was analyzed in RAW264.7 mouse macrophages in response to hemoglobin, heme, ferric ammonium citrate or protoporphyrin treatment or to siRNA mediated knockdown or overexpression of Btb And Cnc Homology 1 or nuclear accumulation of Nuclear Factor Erythroid 2-like. Iron export protein ferroportin promoter activity was analyzed using reporter constructs that contain specific truncations of the iron export protein ferroportin promoter or mutations in a newly identified MARE/ARE element.

RESULTS

We show that iron export protein ferroportin is transcriptionally co-regulated with heme oxygenase 1 by heme, a degradation product of hemoglobin. The protoporphyrin ring of heme is sufficient to increase iron export protein ferroportin transcriptional activity while the iron released from the heme moiety controls iron export protein ferroportin translation involving the IRE in the 5'untranslated region. Transcription of iron export protein ferroportin is inhibited by Btb and Cnc Homology 1 and activated by Nuclear Factor Erythroid 2-like involving a MARE/ARE element located at position -7007/-7016 of the iron export protein ferroportin promoter.

CONCLUSIONS

This finding suggests that heme controls a macrophage iron recycling regulon involving Btb and Cnc Homology 1 and Nuclear Factor Erythroid 2-like to assure the coordinated degradation of heme by heme oxygenase 1, iron storage and detoxification by ferritin, and iron export by iron export protein ferroportin.

Topically applied diacylglycerols increase pigmentation in guinea pig skin

Exposure of human and murine melanocytes in vitro to the diacylglycerol (DAG) 1-oleoyl-2-acetyl-sn-glycerol (OAG) markedly increases melanin production within 24 h. To determine whether OAG can increase melanin production in vivo, increasing concentrations of OAG (10-60 mg/ml) in propylene glycol were applied daily for 5 d to shaved guinea pigs. Dose-dependent increased pigmentation was visible first on days 17-22 and persisted for 10-14 weeks. Peak epidermal melanin content in OAG-treated sites was more than twice that of untreated or vehicle-treated sites, as assessed by computerized image analysis of Fontana-Masson stained biopsy cross sections. In another experiment to assess the mechanism of DAG-mediated pigmentation, guinea pigs received twice daily separate applications of OAG, dipalmitoylglycerol (diC16), dioctanoylglycerol (diC8), each 50 mg/ml, 20 microliters/application, and propylene glycol vehicle alone for 5 d. Increased pigmentation was visible after 10 d in the OAG and diC8 sites but not in diC16 or vehicle sites. These results correlate with the reported ability of these compounds to activate protein kinase C in vitro. In a final experiment, guinea pigs received OAG 25 mg/ml three times daily to one test site, and once daily ultraviolet B (70 mJ/cm2, equivalent to 0.6 minimal erythemal dose) radiation to another for 10 d. The OAG and ultraviolet B test sites developed comparable pigmentation by both clinical and histologic criteria. Our data demonstrate that topically applied DAGs can produce a long-lasting increase in epidermal pigmentation, presumably through protein kinase C activation, which clinically and histologically closely resembles ultraviolet-induced tanning.