A versatile and compact surface plasmon resonance spectrometer based on single board computer.

The widespread diffusion of low-cost but high-performance hardware is enhancing the realization of scientific equipment with features at the research laboratory level. In this paper, we demonstrate hardware implementation of a surface plasmon resonance compact device with high accuracy and measurement times appropriate for many applications. Image acquisition is realized by a Raspberry Pi single board computer with a camera module, and a Python code is used to process data. A flexible optical setup can work in two different configurations, namely, the inspection mode and angle resolved measurement mode. The inspection mode is used to precisely locate the light-emitting diode interrogation beam on the sample, avoiding uneven or faulty regions. The measurement mode allows us to monitor in real time the position of the minimum reflectivity with subpixel resolution. Performance tests show a resolution in the bulk refractive index of 4.9 × 10-6 refractive index units for 10 s acquisition time.

Chromosomal damage and ageing: effect on micronuclei frequency in peripheral blood lymphocytes.

BACKGROUND: Instability in the organization and expression of the genetic material has been hypothesized as the basic mechanism of ageing. OBJECTIVE: To quantify the effect of ageing on chromosomal damage as measured by spontaneous micronuclei (MN) frequency in peripheral blood lymphocytes. METHOD: Analysis of a large population sample from two laboratories applying the cytokinesis-block technique and a third using traditional interphase analysis. The age-related effect on baseline level of micronuclei frequency and on cell proliferation measures was further investigated in a study of peripheral blood samples from healthy subjects. RESULTS: There was an increase of MN frequency with age. The regression lines showed a positive slope and were statistically significant (P< 0.01) with a steeper trend for cytochalasin B-treated samples. An inverse correlation with age was detected for the percentage of binucleated cells in laboratories using cytochalasin B. This study confirms the increase of basal level of MN with age. A decrease by age in proliferation efficiency measured by the percentage of binucleated cells suggests an interference of age-related factors on cell division. CONCLUSION: There is an increase in MN frequency with increasing age.

Genotoxicity biomarkers in the assessment of heavy metal effects in mussels: experimental studies.

Heavy metals are stable and persistent environmental contaminants. The range of metal concentrations is generally below acute thresholds in coastal areas, where recognition of chronic sublethal effects is more relevant. Evidence of long-term adverse effects, such as cancer, due to heavy metals in marine animals comes from a number of field and experimental studies. The mechanism of metal carcinogenicity remains largely unknown, although several lines of experimental evidence suggest that a genotoxic effect may be involved. The aim of our study was to evaluate the sensitivity of genotoxicity tests, alkaline elution and micronucleus test, as biomarkers for the detection of heavy metals in mussels as the sentinel species. Experimental studies were carried out on Mytilus galloprovincialis exposed in aquarium (5 days) to different concentrations of three selected metal salts, CuCl2 (5, 10, 20, 40, 80 micrograms/l/a), CdCl2 (1.84, 18.4, 184 micrograms/l/a), and HgCl2 (32 micrograms/l/a), and to a mixture of equimolar doses of the three metals to study the results of their joint action. Metallothionein quantitation was used as a marker of metal exposure. Lysosomal membrane stability was applied to evaluate the influence of physiological status on genotoxic damage. The ranking of genotoxic potential was in decreasing order: Hg > Cu > Cd. Cu and Hg caused an increase of DNA single-strand breaks and micronuclei frequency. Cd induced a statistical increase of DNA damage, but gave negative results with the micronucleus test. A relationship between genotoxic effects and metallothionein content was observed. Reduction in lysosomal membrane stability with the increasing concentration of heavy metals was also evident.

In vivo studies on genotoxicity of a soil fumigant, dazomet.

Dazomet is a soil fumigant effective against germinating weed seeds, nematodes, soil fungi, and soil insects. Dazomet is primarily used for preplanting control in tobacco and forest nursery crops and is now marketed for a wider range of open field and greenhouse crops (e.g., vegetables, fruits, ornamental plants, lawns, and turfs). Swiss CD1 male and female mice were intraperitoneally treated with dazomet in order to evaluate its potential genotoxicity. DNA damage activity, namely, DNA single-strand breaks, DNA adducts, and increased micronuclei frequency due to treatment with the soil fumigant was observed in the experimental animals. Dose-dependent DNA adduct formation was detected in the liver, kidneys, and lungs of mice. DNA adduct levels in these three organs were 6.0 +/- 0.4 (SD), 4.8 +/- 0.1 (SD), and 2.2 +/- 0.4 (SD) adducts/10(8) nucleotides, respectively, at the highest dose of the soil fumigant tested (90 mg/kg). No adduct formation was observed in control mice. A significant increase in DNA single-strand breaks was detected in the liver and kidneys of mice treated with 100 mg/kg of dazomet (P < 0.05). A significant increase in micronuclei frequency was observed in the bone marrow of mice treated with 100 mg/kg of dazomet (P < 0.05).

Acrocentric chromosome frequency in spontaneous human lymphocyte micronuclei, evaluated by dual-colour hybridization, is neither sex- nor age-related.

The aim of the present paper was to assess the occurrence of acrocentric chromosomes in spontaneous micronuclei (MN) of lymphocytes of 20 subjects (10 males and 10 females) of different ages by means of dual-colour hybridization with pancentromeric and acrocentric-specific DNA probes on the binucleate cells of each subject. MN were found to contain acrocentric chromosome(s) at an average frequency of 26.8%, as compared to a 60% frequency of centromere-positive MN (C + MN). As expected, the percentage of total C + MN increased significantly with increasing age both of all subjects (r = 0.695, p < 0.001) and women (r = 0.814, p < 0.01), while no relationship was found between the frequency of micronuclei containing acrocentric chromosome(s) and donor age. This study indicates that the frequency of MN containing acrocentric chromosomes is neither over-represented nor influenced by age or sex.