Reproductive benefit of oxidative damage: an oxidative stress "malevolence"?

High levels of reactive oxygen species (ROS) compared to antioxidant defenses are considered to play a major role in diverse chronic age-related diseases and aging. Here we present an attempt to synthesize information about proximate oxidative processes in aging (relevant to free radical or oxidative damage hypotheses of aging) with an evolutionary scenario (credited here to Dawkins hypotheses) involving tradeoffs between the costs and benefits of oxidative stress to reproducing organisms. Oxidative stress may be considered a biological imperfection; therefore, the Dawkins' theory of imperfect adaptation of beings to environment was applied to the role of oxidative stress in processes like famine and infectious diseases and their consequences at the molecular level such as mutations and cell signaling. Arguments are presented that oxidative damage is not necessarily an evolutionary mistake but may be beneficial for reproduction; this may prevail over its harmfulness to health and longevity in evolution. Thus, Dawkins' principle of biological "malevolence" may be an additional biological paradigm for explaining the consequences of oxidative stress.

Two novel serum-free media for the culture of Trichomonas vaginalis.

Definitive diagnosis of Trichomonas vaginalis, one of the common causes of sexually transmitted diseases in Turkey, relies on the microscopic examination of both fresh preparations and culture material of genital secretions and urine. The aim of this study was to compare the diagnostic efficacies of two culture media, serum-free TB1 and TB2, including iron and vitamin B12, respectively, with the well-known medium, TYM. Growth rate reached peak levels 48 h in TYM and 72 h in both TB1 and TB2 after inoculation. The highest amount of viable trophozoites has been obtained from TB1, almost equal to TYM but significantly higher than TB2. Fresh preparations obtained from the vaginal secretions of 119 patients have been examined and vaginal samples have been inoculated in TB1, TB2, and TYM. Viable T. vaginalis trophozoites have been detected in ten (8.4%) of fresh preparations and 11 (9.9%) of each medium. It is concluded that serum-free TB1 medium could be used effectively in both the isolation and maintenance of T. vaginalis culture in vitro.