Biting the hand that feeds: anthropogenic drivers interactively make mosquitoes thrive

Anthropogenic stressors on the environment are increasing at unprecedented rates and include urbanization, nutrient pollution, water management, altered land use and climate change. Their effects on disease vectors are poorly understood. A series of full factorial experiments investigated how key human induced abiotic pressures, and interactions between these, affect population parameters of the cosmopolitan disease vector, Culex pipiens s.l. Selected pressures include eutrophication, salinity, mean temperature, and temperature fluctuation. Data were collected for each individual pressure and for potential interactions between eutrophication, salinization and temperature. All experiments assessed survival, time to pupation, time to emergence, sex-ratio and ovipositioning behavior. The results show that stressors affect vector survival, may speed up development and alter female to male ratio, although large differences between stressors exist to quite different extents. While positive effects of increasing levels of eutrophication on survival were consistent, negative effects of salinity on survival were only apparent at higher temperatures, thus indicating a strong interaction effect between salinization and temperature. Temperature had no independent effect on larval survival. Overall, increasing eutrophication and temperatures, and the fluctuations thereof, lowered development rate, time to pupation and time to emergence while increasing levels of salinity increased development time. Higher levels of eutrophication positively impacted egg-laying behavior; the reverse was found for salinity while no effects of temperature on egg-laying behavior were observed. Results suggest large and positive impacts of anthropogenically induced habitat alterations on mosquito population dynamics. Many of these effects are exacerbated by increasing temperatures and fluctuations therein. In a world where eutrophication and salinization are increasingly abundant, mosquitoes are likely important benefactors. Ultimately, this study illustrates the importance of including multiple and combined stressors in predictive models as well as in prevention and mitigation strategies, particularly because they resonate with possible, but yet underdeveloped action plans. NWONWA.1160.1S.210Environmental Biolog

Bioactivity of flaxseed lignans

The lignans derived from flaxseed possess a number of pharmacological properties, both in vitro and in vivo. The ability of these lignans to reduce oxidative stress likely contributes to many of these biological properties. However, it is likely that flaxseed-derived lignans also provide pharmacological activity as a result of their interactions with specific receptors and enzymes within these biological systems. In order to better understand the therapeutic role that flaxseed and flaxseed lignans may play, further studies into the mechanisms of action is warranted. A better understanding of the pharmacology of flaxseed lignans will ultimately lead to appropriate recommendations for their therapeutic use, either as stand-alone therapies or as adjuvants with other pharmaceutical or natural products

Bioactivity of flaxseed lignans

The lignans derived from flaxseed possess a number of pharmacological properties, both in vitro and in vivo. The ability of these lignans to reduce oxidative stress likely contributes to many of these biological properties. However, it is likely that flaxseedderived lignans also provide pharmacological activity as a result of their interactions with specific receptors and enzymes within these biological systems. In order to better understand the therapeutic role that flaxseed and flaxseed lignans may play, further studies into the mechanisms of action is warranted. A better understanding of the pharmacology of flaxseed lignans will ultimately lead to appropriate recommendations for their therapeutic use, either as stand-alone therapies or as adjuvants with other pharmaceutical or natural products

Antioxidant capacity of flaxseed lignans in two model systems

The flaxseed lignans secoisolariciresinol (SECO) and its diglucoside secoisolariciresinol diglucoside (SDG) are reported to have a number of health benefits associated with their consumption that have in part been attributed to their antioxidant properties. In this study the relative antioxidant capacity of the flaxseed lignans vs. BHT was determined in two model systems. First, an antioxidant stoichiometric value was determined for SECO and SDG in a liposomal system as a mimic of lipid peroxidation. Stoichiometric values for SECO (1.5) and SDG (1.2) vs. BHT (2.0) were measured from the lag time for the formation of conjugated dienes; all values were significantly different (P 0.01). There was also no significant difference between SECO or SDG and BHT, suggesting flaxseed lignans may be good alternatives to minimize rancidity in oil-based food products. Copyrigh

AAPH-mediated antioxidant reactions of secoisolariciresinol and SDG

Secoisolariciresinol (SECO 1) is the major lignan found in flaxseed (Linum usitatissimum L.) and is present in a polymer that contains secoisolariciresinol diglucoside (SDG 2). SECO, SDG and the polymer are known to have a number of health benefits, including reduction of serum cholesterol levels, delay in the onset of type II diabetes and decreased formation of breast, prostate and colon cancers. The health benefits of SECO and SDG may be partially attributed to their antioxidant properties. To better understand their antioxidant properties, SECO and SDG were oxidized using 2,2′-azobis(2-amidinopropane), an in vitro model of radical scavenging. The major lignan radical-scavenging oxidation products and their formation over time were determined. SDG was converted to four major products (11-14), which were the result of a phenoxyl radical intermediate. One of these products (13), a dimer of SDG, decomposed under the reaction conditions to form two of the other major products, 12 and 14. SECO was converted to five major products (6-10), two of which (6 and 7) were also the result of a phenoxyl radical intermediate. The remaining products (8, 9 and 10) were the result of an unexpected alkoxyl radical intermediate. The phenol oxidation products were stable under the reaction conditions, whereas two of the alcohol oxidation products (8 and 9) decomposed. In general, only one phenol group on the lignans was oxidized, suggesting that the number of phenols per molecule may not predict radical scavenging antioxidant ability of lignans. Finally, SECO is a superior antioxidant to SDG, and it may be that the additional alcohol oxidation pat