Detection of damage on single- or double-stranded DNA in a population exposed to arsenic in drinking water.

Different studies have suggested an association between arsenic (As) exposure and damage to single-stranded DNA by reactive oxygen species derived from the biotransformation of arsenic. The single strand damages are converted to double strand damage upon interaction with ultraviolet radiation. Analysis of genomic integrity is important for assessing the genotoxicity caused by environmental pollutants. In this study, we compared the concentration of As in drinking water, nutritional status, lifestyle variables, and the level of genotoxicity in an exposed population and a control group. Arsenic content of water was determined using a portable Arsenator® kit. DNA fragmentation was determined using the two-tailed comet assay. Our results show that the exposed population had low nutritional consumption compared to the control group (P < 0.05). Furthermore, the water consumed by the exposed group had As concentration of 14.3 ± 8.4 mg/L, whereas the As level in the water consumed by the control group was 7.7 ± 3.5 mg/L. Analysis shows that the frequency of double strand break (DSB) fragmentation was higher in the population exposed to higher levels of As compared to that of the control group. These results suggest a possible association between the concentration of As in drinking water and lifestyle variables, with increasing fragmentation of DSBs in the exposed population.

Relationship between lymphocyte DNA fragmentation and dose of iron oxide (Fe2O3) and silicon oxide (SiO2) nanoparticles.

At present, the use of nanoparticles is a controversial topic, especially when analyzing their effects in human tissues. Nanoparticles (NPs) can cause oxidative stress by increasing membrane lipids peroxidation and reactive oxygen species, and decreasing intracellular glutathione. Oxidative stress plays an important role in cell signaling and inflammatory responses. It can result in genotoxicity, affect cell proliferation, and induce DNA damage. The objective of this study is to evaluate the genotoxic potential of NPs in lymphocyte DNA. Wistar female rats (N = 45) were sorted in three randomized groups as follows: Group 1 (N = 20); Group 2 (N = 20) and a control group (N = 5). A single dose of iron oxide (Fe2O3) and silicon oxide (SiO2) NPs dissolved in saline solution were administered orally to the rats. Cardiac puncture was performed to extract peripheral blood for genotoxic analysis. DNA fragmentation for lymphocytes was performed. Control rats showed a fragmentation percentage of 11.20 ± 2.16%. Rats exposed to SiO2 and Fe2O3 NPs for 24 h showed statistically significant differences in DNA fragmentation percentages as compared with that of the control group. A lineal dose-response correlation between genotoxic damage and exposure to SiO2 and Fe2O3 NPs was found (r2 = 0.99 and 0.98 for SiO2 and Fe2O3, respectively). In conclusion, we found that exposure to Fe2O3 and SiO2 NPs can cause DNA fragmentation in lymphocytes in a dose-dependent manner.

Formaldehyde induces DNA strand breaks on spermatozoa and lymphocytes of Wistar rats.

Formaldehyde (FA) interacts with biological molecules such as DNA and it induces DNA-protein cross-links (DPCs), oxidative stress, reactive oxygen species (ROS), methylation, chromosomal damage, fragmentation, and adducts of DNA, which are considered the most important genotoxic effects caused by exposure to FA. The purpose of this study was to evaluate the percentage of DNA fragmentation on lymphocytes and spermatozoa from Wistar rats exposed to different doses of FA. The results about the percentage of fragmentation of DNA in lymphocytes and spermatozoa, were statistical different from controlled group versus treated groups respectively to (p < 0.05). Pathological changes were observed in the seminiferous tubules, especially in rats exposed to 30 mg/kg of FA. This study provided additional evidence supporting that FA induces DNA strand breaks in both cells and therefore genotoxic damage in Wistar rats.

Sperm chromatin dispersion by formaldehyde in Wistar rats.

Formaldehyde (FA) is an environmental xenobiotic, which is genotoxic and carcinogenic to humans and animals; it induces DNA damage, mutations, and clastogenicity during critical cytogenetic events. FA-mediated oxidative stress is an important mechanism that has been associated with the induction of cytotoxic and genotoxic damage. Therefore, the objective of this study was to evaluate the dispersion of sperm chromatin and reproductive parameters induced by exposure to different concentrations of FA in Wistar rats. Compared to the percentage of sperm with fragmented DNA in the control group (18.10 ± 8.62%), the percentage of sperm with fragmented DNA increased following exposure to 5, 10, and 30 mg FA/kg body weight (29.60 ± 8.44, 85.20 ± 20.94 and 96.0 ± 7.87, respectively; P = 0.0001). Histopathological alterations were evident, especially in the seminiferous tubules. In conclusion, this study provides experimental evidence concerning the genotoxicity of FA, with particular reference to the decreased sperm concentration and motility and increased dispersion of DNA chromatin in rats.

Lipid, instrumental color and sensory characteristics of ground beef produced using trisodium phosphate, cetylpypiridinium chloride, chlorine dioxide or lactic acid as multiple antimicrobial interventions.

Beef trimmings were treated with 0.5% cetylpyridinium chloride followed by 10% trisodium phosphate (CT), 200-ppm chlorine dioxide followed by 0.5% cetylpyridinium chloride (CLC), 200-ppm chlorine dioxide followed by 10% trisodium phosphate (CLT), or 2% lactic acid followed by 0.5% cetylpyridinium chloride (LC). The trimmings were ground, packaged and sampled at 0, 1, 2, 3 and 7 days of simulated retail display and compared with an untreated control (C) for instrumental color, sensory color and odor and TBARS (Thiobarbituric acid reactive substances) characteristics. Ground beef from the LC and CLC treatments were lighter (P <0.05; L*) than C. The LC and CT ground beef samples were similar (P > 0.05) in vividness to C. On day 3, CT was scored redder (P <0.05) than C. Therefore, the use of CT, CLT, CLC and LC had little impact on ground beef color and CT improved ground beef color shelf life.

The impact of single antimicrobial intervention treatment with cetylpyridinium chloride, trisodium phosphate, chlorine dioxide or lactic acid on ground beef lipid, instrumental color and sensory characteristics.

The effects of antimicrobial agents on ground beef were evaluated to determine if instrumental color, sensory or odor characteristics were impacted. Trimmings were treated with 0.5% cetylpyridinium chloride (CPC), 200-ppm chlorine dioxide (CLO), 0.5% lactic acid (LA), 10% trisodium phosphate (TSP), or an untreated control (C). Ground beef made from trimmings with CLO and TSP were similar (P > 0.05) in L(∗) values to the control; however, samples were redder (a(∗); P<0.05) than the control. Likewise, sensory panelists found ground beef from the CPC and TSP treatments redder (P<0.05) for worst point color than the control by day 2 of display. The CLO, CPC and TSP treatments were similar (P>0.05) to the control in beef odor intensity until day 3 of display. Therefore, the use of antimicrobial agents on beef trimmings may not adversely affect, and may improve bulk ground beef color and odor characteristics.

The effects of multiple antimicrobial interventions on processing, lipid, textural, instrumental color and sensory characteristics when used in a ground beef patty production system.

The impact of multiple antimicrobial interventions on ground beef processing, lipid, textural, instrumental color and sensory characteristics were evaluated. Beef trimmings were treated with 0.5% cetylpyridinium chloride followed by 10% trisodium phosphate (CT), 200-ppm chlorine dioxide followed by 0.5% cetylpyridinium chloride (CLC), 200-ppm chlorine dioxide followed by 10% trisodium phosphate (CLT), or 2% lactic acid followed by 0.5% cetylpyridinium chloride (LC) and compared to an untreated control (C). Sensory panelists found LC and CT treatments similar (P>0.05) in grinding ability to C. By day 2 of display, CT, CLT and LC patties were redder (a(∗); P<0.05) than C. Sensory panelists found CT patties redder (P<0.05) than C by day 2 of display. Sensory panelists found CT and CLT juicier than C. Therefore, the use of these multiple antimicrobial intervention agents on beef trimmings may improve sensory characteristics and shelf-life of ground beef patties.

Effects of chlorine dioxide, cetylpyridinium chloride, lactic acid and trisodium phosphate on physical, chemical and sensory properties of ground beef.

The impact of beef trimmings treated with either 0.5% cetylpyridinium chloride (CPC), 200-ppm chlorine dioxide (CLO), 2% lactic acid (LA) or 10% trisodium phosphate (TSP) and an untreated control (C) prior to grinding, on instrumental color, sensory characteristics, TBARS values, pH and Lee-Kramer shear under simulated retail display were evaluated. Trimmings were ground, pattied and sampled at 0, 1, 2, 3 and 7 days of display. Patties from LA, CPC and CLO treatments were lighter (L*; P<0.05) and TSP patties were redder (a*; P<0.05) than C. Panelists found TSP and CPC patties were similar or superior in beef and off odor to C on days 3 and 7 of display. Therefore, treatment of beef trimmings before grinding with TSP, CPC, CLO or LA may not only improve ground beef safety, but maintain or enhance patty shelf life.