Carbon dioxide concentration and nitrogen input affect the C and N storage pools in Amanita muscaria-Picea abies mycorrhizae

We studied the influence of elevated atmospheric CO2 concentration ([CO2]) on the vacuolar storage pool of nitrogen-containing compounds and on the glycogen pool in the hyphal sheath of Amanita muscaria (L. ex Fr.) Hooker-Picea abies L. Karst. mycorrhizae grown with two concentrations of ammonium in the substrate. Mycorrhizal seedlings were grown in petri dishes on agar containing 5.3 or 53 mg N l(-1) and exposed to 350 or 700 microl CO2 l(-1) for 5 or 7 weeks, respectively. Numbers and area of nitrogen-containing bodies in the vacuoles of the mycorrhizal fungus were determined by light microscopy linked to an image analysis system. The relative concentration of nitrogen in the vacuolar bodies was measured by electron energy loss spectroscopy (EELS). Glycogen stored in the cytosol was determined at the ultrastructural level by image analysis after staining the sections (PATAg test). Shoot dry weight, net photosynthesis and relative amounts of N in vacuolar bodies were greater at the higher N and CO2 concentrations. The numbers and areas of vacuolar N-containing bodies were significantly greater at the higher N concentration only at ambient [CO2]. In the same treatment the percentage of hyphae containing glycogen declined to nearly zero. We conclude that, in the high N/low [CO2] treatment, the mycorrhizal fungus had an insufficient carbohydrate supply, partly because of increased amino acid synthesis by the non-mycorrhizal rootlets. When [CO2] was increased, the equilibrium between storage of glycogen and N-containing compounds was reestablished.     

Estrogen and androgen receptor expression in relation to steroid concentrations in the adult boar epididymis

The steroid hormone regulation of the epididymis in a high estrogen producing animal like the boar is not currently understood. To test the hypothesis that the boar epididymis is an estrogen and androgen responsive tissue, the presence of estrogen and androgen receptors, in conjunction with steroid hormone concentrations were investigated in the boar epididymis. Epididymal (caput, corpus, cauda) and testicular samples of boars (1–2.5 years; n = 5) were collected for immunolocalization of estrogen receptor alpha (ER), estrogen receptor beta (ERβ) and androgen receptor (AR). Concentrations of testosterone, estradiol and estrogen conjugates (EC) in the tissue were also determined. AR and ERβ were localized in the principal and basal cells of all three epididymal regions. ER was localized in the principal cells of the caput, some cells of the corpus and was not present in the cauda. Testosterone (p < 0.0001), estradiol (p < 0.0001) and EC (p < 0.005) were significantly lower in the epididymis compared with the testis. The epididymal regions were not significantly different from each other for testosterone (p > 0.15) or estradiol (p > 0.09). EC were significantly higher in the corpus than either the caput (p = 0.003) or cauda (p = 0.002). These results suggest that the boar epididymis is responsive to both estrogens and androgens and that both steroid hormones are important for proper epididymal function. Since testosterone and estradiol concentrations are similar throughout the epididymis, regional differences in steroid hormone regulation are likely due to differences in receptor expression.     

Effects of conservation education on reasons to conserve biological diversity

To examine factors that might influence how people subscribe to different reasons for conserving biological diversity, we modified Ehrenfeld's [American Scientist 64 (1976) 660] classic reasons for conserving species and habitats into consumption, tourism, medicine, science, education, environmental baselines, ecosystem services, intrinsic value, and added another, human cultural heritage. We then explored the opinions of undergraduates enrolled in a classic conservation biology course, or a people and conservation course, about these nine arguments, using a 27-statement questionnaire. By matching responses made before and after each course, we found that students, in general, became more committed to using most of Ehrenfeld's arguments but that this was highly contingent on which conservation course that they had taken. None became committed to the argument that linked wildlife conservation to human culture, however. Course and grade that students attained influenced the extent to which students were sympathetic to different arguments but gender had no effect. These findings show that the type of conservation knowledge imparted to students makes them differentially sympathetic to many of the arguments used to advocate wildlife conservation.     

Effects of retirement on lifestyle in relation to changes in weight and waist circumference in Dutch men: a prospective study

OBJECTIVE: To study changes in lifestyle in relation to changes in body weight and waist circumference associated with occupational retirement in men. DESIGN: A prospective cohort study with 5 years of follow-up. At baseline and at follow-up, questionnaires were completed and body weight and waist circumference were measured. SETTING: The Doetinchem Cohort Study, consisting of inhabitants of Doetinchem, a town in a rural area of The Netherlands.Subjects: In total 288 healthy men aged 50-65 years at baseline, who either remained employed or retired over follow-up. RESULTS: The effect of retirement on changes in weight and waist circumference was dependent on type of former occupation. Increase in body weight and waist circumference was higher among men who retired from active jobs (0.42 kg year(-1) and 0.77 cm year(-1), respectively) than among men who retired from sedentary jobs (0.08 kg year(-1) and 0.23 cm year(-1), respectively). Weight gain and increase in waist circumference were associated with a decrease in fruit consumption and fibre density of the diet, with an increase in frequency of eating breakfast, and with a decrease in several physical activities, such as household activities, bicycling, walking and doing odd jobs. CONCLUSION: Retirement was associated with an increase in weight and waist circumference among those with former active jobs, but not among those with former sedentary jobs. Retirement may bring opportunities for healthy changes in diet and physical activity, which could be used in health promotion programmes.     

Genetic progress of upland rice (Oryza sativa L.) lines for disease resistance

The rice crop is affected by diseases throughout its cycle, impacting negatively on grain yield and quality. The control of the disease impact can be accomplished via crop breeding, using highly multiple resistant genotypes. This study aimed to evaluate the efficiency of multiple-character and specific selection of multiple resistance to major culture-associated diseases (neck blast, leaf scald and grain discoloration) in rice lines of the Upland Rice Genetic Breeding Program. The experiments were conducted in 35 sites during 12 agricultural years, where 124 lines were evaluated for the severity of fungal diseases, under natural field conditions. Multiple parameters were calculated based on the diseases´ scores: genetic, phenotypic and environmental variances, heritability, selection gain, renewal rate, and genetic and renewal progress. Genetic variance for the disease resistance was identified in the population, and the selection gain for multiple-character selection was of 3.16 year⁻¹ throughout the breeding process with a renewal rate of over 35%. The programme has showed efficiency in selecting multiple resistant genotypes to the mentioned diseases, highlighting genotypes with high potential for market release.     

The comparison of phosphorus-nitrogen and sulfur-phosphorus-nitrogen on the anti-flammability and thermal degradation of cotton fabrics

Phosphorus-nitrogen (P-N) or sulfur (S) containing compounds are well known for their effectiveness as flame retardant additives for many polymeric systems. When either phosphorus or nitrogen is combined with sulfur, the new systems prove to be successful combinations. This research aims to learn the impact of two systems, P-N and S-P-N, on the flammability and thermal properties of cotton fabrics. The process includes the synthesis of two compounds, tetraethyl piperazine-1,4-diyldiphosphonate (TEPP) and O,O,O',O'-tetramethyl piperazine-1,4-diyldiphosphonothioate (TMPT), and the evaluation of flammability, thermal degradation, and surface morphology of the treated fabrics. Both compounds exhibit similar burning behavior and show improved flame retardancy and thermal properties when used on various cotton fabrics. Some unique flame retardant properties for the two compounds are also disclosed.     

Differences in benthic cover inside and outside marine protected areas on the Great Barrier Reef: influence of protection or disturbance history?

• 1. Marine protected areas (MPAs) are being used increasingly to manage and protect marine resources. Most studies of MPAs have focused on fish. In this study, the influence of MPA protection on coral reef benthic organisms on the Great Barrier Reef (GBR) was investigated. In addition, the interaction between protection and natural disturbance history was examined.
• 2. Differences in benthic cover inside and outside MPAs were assessed at 15 pairs of Protected and General Use reefs on the GBR using annual monitoring data from the Australian Institute of Marine Science's Long‐Term Monitoring Programme (LTMP). At each reef, benthic cover was determined using a benthic video survey at three sites, with each site consisting of five 50 m transect lines separated by at least 250 m running parallel to the reef crest at 6–9 m depth.
• 3. Benthic cover was related to both protection status and disturbance history, but natural perturbations exerted a stronger influence on benthic cover than did protection status. The influence of natural perturbation was most noticeable for hard coral.
• 4. Most reefs where no natural disturbance events had occurred (‘undisturbed reefs’) had higher hard coral cover and lower soft coral cover than General Use reefs. While the high levels of hard coral on Protected reefs may be a result of protection status, it might also have resulted from selection bias that occurred during the initial zoning of the Great Barrier Reef Marine Park (i.e. managers may have given protection status to reefs with high coral cover).
• 5. These results are likely influenced by the relatively low intensity of human use, both on the Great Barrier Reef in general and at the particular monitoring sites studied. Over time, as local populations and tourism increase, the effect of protection may become more evident at LTMP sites. Copyright © 2009 John Wiley & Sons, Ltd.

     

Regression spline mixed models: A forestry example

In this article, regression splines are used inside linear mixed models to explore nonlinear longitudinal data. The regression spline bases are generated using a single knot chosen using biological information—a knot position supported by an automated knot selection procedure. A variety of inferential procedures are compared. The variance in the data was closely modeled using a flexible model-based covariance structure, a robust method and the nonparametric bootstrap, while the variance was underestimated when independent random effects were assumed.     

Actions of azadirachtin,a plant allelochemical,against insects

Investigations of the antifeedant mode of action of azadirachtin and four synthetic analogues, 22,23-dihydroazadirachtin, 3-tigloylazadirachtol, 11-methoxydihydroazadirachtin and 22,23-bromoethoxydihydroazadirachtin have revealed that both polyphagous and oligophagous insects are behaviourally responsive to azadirachtin, with the most responsive species being able to differentiate extremely small changes in the parent molecule. In Lepidoptera the antifeedant response is correlated also with increased neural activity of the chemoreceptors. When locusts are treated on crop plants, the antifeedant and physiological actions of azadirachtin and analogues work in concert and result in feeding deterrence, growth and moulting aberrations and mortality with the same order of potency as for antifeedancy. Specific binding studies using [³H]dihydroazadirachtin carried out on locust testes and Spodoptera Sf9 cells have shown that the competitive binding of the different analogues of azadirachtin to these binding sites occurs in a similar order of potency to that found with antifeedant and IGR bioassays. This suggests a causal link between specific binding to membrane proteins and the ability of the molecule to exert biological effects. © 1998 Society of Chemical Industry