Integrative assessment of low-dose gamma radiation effects on <i>Daphnia magna</i> reproduction: Toxicity pathway assembly and AOP development

High energy gamma radiation is potentially hazardous to organisms, including aquatic invertebrates. Although extensively studied in a number of invertebrate species, knowledge on effects induced by gamma radiation is to a large extent limited to the induction of oxidative stress and DNA damage at the molecular/cellular level, or survival, growth and reproduction at the organismal level. As the knowledge of causal relationships between effects occurring at different levels of biological organization is scarce, the ability to provide mechanistic explanation for observed adverse effects is limited, and thus development of Adverse Outcome Pathways (AOPs) and larger scale implementation into next generation hazard and risk predictions is restricted. The present study was therefore conducted to assess the effects of high-energy gamma radiation from cobalt-60 across multiple levels of biological organization (i.e., molecular, cellular, tissue, organ and individual) and characterize the major toxicity pathways leading to impaired reproduction in the model freshwater crustacean Daphnia magna (water flea). Following gamma exposure, a number of bioassays were integrated to measure relevant toxicological endpoints such as gene expression, reactive oxygen species (ROS), lipid peroxidation (LPO), neutral lipid storage, adenosine triphosphate (ATP) content, apoptosis, ovary histology and reproduction. A non-monotonic pattern was consistently observed across the levels of biological organization, albeit with some variation at the lower end of the dose-rate scale, indicating a complex response to radiation doses. By integrating results from different bioassays, a novel pathway network describing the key toxicity pathways involved in the reproductive effects of gamma radiation were proposed, such as DNA damage-oocyte apoptosis pathway, LPO-ATP depletion pathway, calcium influx-endocrine disruption pathway and DNA hypermethylation pathway. Three novel AOPs were proposed for oxidative stressor-mediated excessive ROS formation leading to reproductive effect, and thus introducing the world's first AOPs for non-chemical stressors in aquatic invertebrates.publishedVersio

Quality protein maize (QPM) for school feeding in Ethiopia: stakeholders consultation, sensory evaluation and potential impact

Recently there is an increased attention among policy and research practitioners on the link between school feeding programs (SFP) and agricultural development. Through purchases and procurement of locally produced foods, SFP are thought to enhance the domestic production and demand for food and stimulate local agricultural economy. Quality protein maize (QPM) varieties, which are being disseminated in Ethiopia by CIMMYT, are superior to conventional maize (CM) varieties in their protein quality. However, for QPM to be adopted in SFP, sensory acceptance by the end-users should be assessed, specifically when the targets beneficiaries are young children. Furthermore, the potential challenges and opportunities for its supply to SFPs should be analysed by involving pertinent stakeholders involved in maize value chain. Thus, the objective of this study is to assess sensory evaluation of QPM among 95 adolescent girls in two primary schools in Ethiopia on a popular local porridge-like product Kinchie through central location testing, and also assess potential challenges and opportunities in QPM production and distribution through stakeholders’ consultation. Results of sensory evaluation showed that Kinchie made from QPM varieties, both yellow QPM (BHPQY 545) and white QPM (AMHP 760Q), were much appreciated for aroma, taste and overall appreciations. Nevertheless, among QPM varieties, the students liked the Kinchie made from yellow QPM (BHQPY 545) more than Kinchie made from a white colored QPM (AMH 760Q) in all sensory attributes except appearance. The result also showed that the effect of order of food presentation had a significant and positive effect only for aroma (P< .05). Stockholder consultation result also showed that local maize grain producers and traders and other institutions involved in maize value chain were enthusiastic to engage in QPM production and supply through contract farming. In conclusion, consumer acceptance is unlikely to impede uptake and impact of QPM use in the place of CM varieties in SFPs.377-38

Integrative assessment of low-dose gamma radiation effects on Daphnia magna reproduction: Toxicity pathway assembly and AOP development

High energy gamma radiation is potentially hazardous to organisms, including aquatic invertebrates. Although extensively studied in a number of invertebrate species, knowledge on effects induced by gamma radiation is to a large extent limited to the induction of oxidative stress and DNA damage at the molecular/cellular level, or survival, growth and reproduction at the organismal level. As the knowledge of causal relationships between effects occurring at different levels of biological organization is scarce, the ability to provide mechanistic explanation for observed adverse effects is limited, and thus development of Adverse Outcome Pathways (AOPs) and larger scale implementation into next generation hazard and risk predictions is restricted. The present study was therefore conducted to assess the effects of high-energy gamma radiation from cobalt-60 across multiple levels of biological organization (i.e., molecular, cellular, tissue, organ and individual) and characterize the major toxicity pathways leading to impaired reproduction in the model freshwater crustacean Daphnia magna (water flea). Following gamma exposure, a number of bioassays were integrated to measure relevant toxicological endpoints such as gene expression, reactive oxygen species (ROS), lipid peroxidation (LPO), neutral lipid storage, adenosine triphosphate (ATP) content, apoptosis, ovary histology and reproduction. A non-monotonic pattern was consistently observed across the levels of biological organization, albeit with some variation at the lower end of the dose-rate scale, indicating a complex response to radiation doses. By integrating results from different bioassays, a novel pathway network describing the key toxicity pathways involved in the reproductive effects of gamma radiation were proposed, such as DNA damage-oocyte apoptosis pathway, LPO-ATP depletion pathway, calcium influx-endocrine disruption pathway and DNA hypermethylation pathway. Three novel AOPs were proposed for oxidative stressor-mediated excessive ROS formation leading to reproductive effect, and thus introducing the world's first AOPs for non-chemical stressors in aquatic invertebrates