Responses of Four Australian Tree Species to Toxic Concentrations of Copper in Solution Culture

ABSTRACT

In Australia, metal-contaminated sites, including those with elevated levels of copper (Cu), are frequently revegetated with endemic plants. Little is known about the responses of Australian plants to excess Cu. Acacia holosericea, Eucalyptus crebra, Eucalyptus camaldulensis, and Melaleuca leucadendra were grown in solution culture with six Cu treatments (0.1 to 40 μ M). While A. holosericea was the most tolerant to excess Cu, all of the species tested were sensitive to excess Cu when compared with exotic tree and agricultural species. The critical external concentrations for toxicity were < 0.7 μM for all species tested. There was little differentiation between shoot-tissue Cu concentrations in normal versus treated plants, thus, the derivation of critical shoot concentrations was possible only for the most tolerant species, A. holosericea. Critical root Cu concentrations were approximately 210 μg g^?1 (A. holosericea), 150 μ g g^?1 (E. crebra), 25 μ g g^?1 (E. camaldulensis), and 165 μ g g^?1 (M. leucadendra). These results provide the first comprehensive combination of growth responses, critical concentrations, and toxicity symptoms for three important Australian genera for use in the management of Cu-contaminated sites.     

Do gender, nationality, or academic age affect review decisions? An analysis of submissions to the journal Biological Conservation

Recent papers have considered whether the present system of single-blind reviewing results in bias against women or other groups of authors in biological journals. If so, double-blind reviewing might be an alternative approach that avoids such bias. We investigated the effects of gender, nationality (English-speaking countries only), academic age, year of review, and handling editor on the decisions made on a sample of 1856 papers submitted to the journal Biological Conservation between 2004 and 2007. There is no evidence of differences in acceptance rates among genders, nationalities, academic age, or year, nor is there evidence for interactions among these factors. Individual handling editors differed in the proportions of papers that they accepted, rejected following review, and rejected without review, but did not show biases based on any of the factors we examined. Overall, we did not find evidence supporting a change in the present review system, although the low rate of acceptance of papers from certain non-English-speaking countries is an issue that needs to be addressed. We believe that these types of audits of the editorial system are necessary, so that all submitting authors feel that the editorial process is fair, unbiased and rigorous.     

Characterisation of adult green lacewing (Chrysoperla carnea) digestive physiology: impact of a cysteine protease inhibitor and a synthetic pyrethroid

BACKGROUND: In spite of concern regarding potential non‐target effects of GM crops, few studies have compared GM pest control with conventional methods. The impacts of cypermethrin and oilseed rape expressing oryzacystatin‐1 (OC‐1) were compared in this study on the predator Chrysoperla carnea (Stephens). RESULTS: Adults fed purified rOC‐1 showed a subtle shift in digestive protease profile, with an increasing reliance on serine proteases (chymotrypsin), increase in aspartic proteases and a slight reduction in elastase activity. Although there were no effects on mortality, onset of oviposition was delayed; however, once egg production commenced, egg laying and hatching success rates were comparable with those of controls. Oryzacystatin‐1 expressed in pollen showed no detrimental effects. Cypermethrin had no effect on mortality owing to high levels of non‐specific esterase activity resulting in partial breakdown of the insecticide. In spite of this, there was a significant delay in onset of oviposition and a significant reduction in egg production and viability. CONCLUSION: This study demonstrates the potential for pest management to impact on predators, but importantly it highlights the ability of the predator to detoxify/respond to treatments with different modes of action. In this case, exposure to an insecticide carried a greater fitness cost than exposure to a protease inhibitor expressed in transgenic crops. Copyright © 2009 Society of Chemical Industry     

Phytoestrogen content of foods of animal origin: dairy products, eggs, meat, fish, and seafood

Dietary phytoestrogens may be involved in the occurrence of chronic diseases. Reliable information on the phytoestrogen content in foods is required to assess dietary exposure and disease risk in epidemiological studies. However, existing analyses have focused on only one class of these compounds in plant-based foods, and there is only little information on foods of animal origin, leading to an underestimation of intake. This is the first comprehensive study of phytoestrogen content in animal food. We have determined the phytoestrogen content (isoflavones: biochanin A, daidzein, formononetin, genistein, and glycitein; lignans: secoisolariciresinol and matairesinol; coumestrol; equol; enterolactone; and enterodiol) in 115 foods of animal origin (including milk and milk-products, eggs, meat, fish, and seafood) and vegetarian substitutes using liquid chromatography-mass spectrometry (LC-MS) with (13)C-labeled internal standards. Phytoestrogens were detected in all foods analyzed; the average content was 20 microg/100 g of wet weight (isoflavones, 6 microg/100 g; lignans, 6 microg/100 g; equol, 3 microg/100 g; and enterolignans, 6 microg/100 g). In infant soy formula, 19 221 microg/100 g phytoestrogens were detected (compared to 59 microg/100 g in non-soy formula). Our study shows that all foods analyzed contained phytoestrogens and most foods (except for fish, seafood, and butter) contained mammalian phytoestrogens (enterolignans and equol). This is the first comprehensive study of phytoestrogen content of foods of animal origin and will allow for a more accurate estimation of exposure to dietary phytoestrogens.     

Subacute ruminal acidosis (SARA) in grazing Irish dairy cows

Subacute ruminal acidosis (SARA) is a significant production disease of dairy cattle. Previous concerns have been raised over the occurrence of SARA in pasture-fed dairy cattle and the potential consequences of laminitis and lameness. Highly digestible perennial rye grass contains high concentrations of rapidly fermentable carbohydrate and low concentrations of physical effective fibre that may result in SARA. This study conducted a point prevalence survey of rumen health status in grazing Irish dairy cattle fed predominantly perennial rye grass-based pasture. The survey assessed rumen fluid, animal health status, milk production data and pasture composition. A total of 144 cows between 80 and 150 days in milk were sampled on 12 farms. Eleven percent of cows were classified as affected with SARA (pH < or = 5.5), 42% were marginal (pH 5.6-5.8) and 47% were normal (pH>5.8). The study showed that low rumen pH is prevalent in grazing Irish dairy cattle consuming perennial rye grass-based pasture and raises concerns regarding effective pasture utilisation and possible consequences for animal health.