Electrically generated negative air ions (ENIs) have been widely used to improve indoor air quality. However, the effects of ENIs reported so far were inconsistent due to the variance in test systems, end points detected and the exposure methods. In this study, a simple model organism, the nematode Caenorhabditis elegans, was used as an in vivo system to assess the biological effects of continuous ENIs exposure. The worms were exposed to ENIs in a 10(5) 10(5) ions/cm(3) chamber and their development period, lifespan, brood size and germline cell apoptotisis were examined. The results showed that ENIs decreased the development period, shortened the lifespan, increased the germline cell apoptosis and reduced the brood size, suggesting that persistent ENIs exposure might induce damage in C. elegans. To further scrutinize the mechanisms underlying these damage effects, a reactive oxygen species (ROS) sensitive C. elegans, mev-1(kn1) mutant, and sod-3::gfp transgenic strains were used. The results showed that the persistent ENIs exposure significantly shortened the lifespan of mev-1(kn1) mutant compared to the wild type. Moreover, levels of SOD-3 were increased in an exposure time-dependent manner. Treatment with either DMSO or l-ascorbic acid, effective ROS scavengers, could rescue the upregulation of germline cell apoptosis and SOD-3 level induced by ENIs exposure, indicating that ROS may be involved in ENIs exposure-induced damaging effects.
"Yates et al. (1986) reported that exposure to large quantities of negative ions (>300000 ions cm -3 ) damage pig and rabbit tissues as a result of superoxide anion (O 2 -) degeneration. Similary, persistant exposure of Ceanorhabditis Elegans (simple model organisms, nematode) to electrically generated NAI at 10 5 ion/cm 3 concentration, caused damage during development, ageing and reproduction (Cai et al. 2008). Contrary to these reports, the data presented in this study, showed no signs of tissue damage in rats. "
[Show abstract][Hide abstract] ABSTRACT: Physiological anthropology presently covers a very broad range of human knowledge and engineering technologies. This study reviews scientific inconsistencies within a variety of areas: sitting posture; negative air ions; oxygen inhalation; alpha brain waves induced by music and ultrasound; 1/f fluctuations; the evaluation of feelings using surface electroencephalography; Kansei; universal design; and anti-stress issues. We found that the inconsistencies within these areas indicate the importance of integrative thinking and the need to maintain the perspective on the biological benefit to humanity. Analytical science divides human physiological functions into discrete details, although individuals comprise a unified collection of whole-body functions. Such disparate considerations contribute to the misunderstanding of physiological functions and the misevaluation of positive and negative values for humankind. Research related to human health will, in future, depend on the concept of maintaining physiological functions based on consistent science and on sustaining human health to maintain biological welfare in future generations.
"Third, the average life span of the mev-1 worms was significantly lower than that of N2. The proportional decrease in life span from mev-1 to N2 ancestral control worms ($17%) was slightly lower than reported values, which vary from 20 to 49% (Ishii et al. 1990; Adachi et al. 1998; Hartman et al. 2001; Yanase et al. 2002; Cai et al. 2008), likely in part because of our very small sample size (N = 5/replicate). Additionally, mev-1 worms tended to develop more slowly, as documented by others (e.g., Ishii et al. 1990; Yasuda et al. 1999), although the development rates of the mev-1 worms were not different enough from the N2 that we had to lengthen the intervals between MA bottlenecks, as we have in previous studies (e.g., Baer et al. 2010). "
[Show abstract][Hide abstract] ABSTRACT: Variation in rates of molecular evolution has been attributed to numerous, interrelated causes, including metabolic rate, body size, and generation time. Speculation concerning the influence of metabolic rate on rates of evolution often invokes the putative mutagenic effects of oxidative stress. To isolate the effects of oxidative stress on the germline from the effects of metabolic rate, generation time, and other factors, we allowed mutations to accumulate under relaxed selection for 125 generations in two strains of the nematode Caenorhabditis elegans, the canonical wild-type strain (N2) and a mutant strain with elevated steady-state oxidative stress (mev-1). Contrary to our expectation, the mutational decline in fitness did not differ between N2 and mev-1. This result suggests that the mutagenic effects of oxidative stress in C. elegans are minor relative to the effects of other types of mutations, such as errors during DNA replication. However, mev-1 MA lines did go extinct more frequently than wild-type lines; some possible explanations for the difference in extinction rate are discussed.
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