Etude de la nutrition potassique du sorgho I‐ incidence du remplacement du potassium par le sodium sur la teneur en cations des feuilles

Abstract

Grain sorghum plants were grown in nutritive solution culture under variable potassium concentrations from 0.5 to 6.0 meq/l, Na replacing K in deficient solutions. Leaves were analysed for K⁺, Na⁺, Ca⁺⁺ and Mg⁺⁺.

Potassium deficiency has no effect on the total amount of cations, but the decrease of K in deficient leaves is correlated with an increase of Na⁺, Ca⁺⁺ and Mg⁺⁺. Evidence of antagonism between K and divalent cations in given, but, in the most deficient leaves, magnesium instead of calcium balances for the diminution of potassium.     

Comparison of buffet and à la carte serving at worksite canteens on nutrient intake and fruit and vegetable consumption

OBJECTIVE: To evaluate the nutritional composition of worksite canteen lunches and to examine the impact of two meal serving systems on employee intake, i.e. buffet style with a fixed price for a varied number of dishes and à la carte style with a separate price for each item on the menu. DESIGN: Laboratory technicians observed employees' food selection and collected identical dishes. Food items were weighed separately to calculate the content of fruit and vegetables. The content of protein, fat and ash of each dish was chemically analysed and the carbohydrate and energy content calculated. SETTING: Fifteen randomly chosen worksite canteens in Denmark: eight canteens serving buffet style and seven canteens with an à la carte line. SUBJECTS: one hundred and eighty randomly chosen employees having lunch at the worksite canteens. RESULTS: The average percentage energy from fat was 37 +/- 12 among men and 33 +/- 12 among women. No association was found between the meal serving system and energy intake or macronutrient composition. Eating at canteens serving buffet style, on the other hand, was associated with an increased intake of fruit and vegetables, on average 76 g, and a lower energy density of the food for both genders. CONCLUSION: The results highlight the possibilities of promoting healthy food choices in the catering sector and the need to identify models of healthy catering practice. Serving buffet style appears to be a promising strategy in order to increase fruit and vegetable consumption in food served away from home.     

Modalités de la contamination de deux chaînes trophiques dulçaquicoles par le cobalt 60

Introduction

A previous work (Amiard-Triquet and Foulquier, 1978) has covered the dynamics of water-borne contamination in organisms included into two freshwater food-chains: Here, we report the results obtained about the contamination of the same species bothvia water and food.

Experimental Procedures (Table I)

The specimens were continuously immersed in contaminated water and received radioactive food. The radioactivity level was the same for the water in which they were immersed and for the water used in the contamination of their prey. The level was adjusted at 4 μCi/l for the carp food-chain and 0.4 μCi/l for that of the crayfish. Daphnia were reared in a medium compo?ed of 2/5 of soil extract and 3/5 of river water (Table II). They were fed bacteria developed in this medium or uponChlorella cultivated apart and then introduced in the rearing tanks. The bulk of the medium varied between 5 and 30 l. The influence of the various components of the rearing medium on the physico-chemical form of⁶⁰Co was studied by chromatographic techniques using ion-exchange resins. Three groups of fiftyLymnaea were placed in three tanks containing 30 l of river water.Elodea which composed their food were immersed in the same tanks. Crayfishes and carps were reared in individual containers. Five times per week, they received, respectively, oneLymnaea or one hundredDaphnia. Water was changed and contaminated again each week.

Results

NH ₄ ⁺ ions produced in the rearing medium with organic metabolites extracted byDaphnia do not affect the physico-chemical form of⁶⁰Co. On the contrary, anionic complex forms appear under the influence of river water or soil extract components. The radioactivity ofDaphnia evolves during the contamination experiment as a function of the biological availability of the different physico-chemical states of cobalt. The maximum value of the overall contamination factor C^* is 70.3 after one week of experiment; the minimum value, 8.6 after ten months. The contamination dynamics for the other species are presented in Figures 3 and 4. The mean values at equilibrium for⁶⁰Co concentration in the organisms and for overall contamination factor C are assembled in Table III.

Discussion and Conclusions

Daphnia likely discriminate the different physico-chemical forms of⁶⁰Co, the availability of anionic complexes being low. The vector of contamination, water alone or both food and water, has not a striking influence upon the⁶⁰Co concentration in carp,Lymnaea and crayfish. The most highly developed species from the zoological point of view are the weakest in this concentration: Teleosts are not so contaminated as Crustaceans which are not so contaminated as Mollusks. On the other hand, the secondary consumers (carp, crayfish) are not so contaminated as the primary consumers (Lymnaea, Daphnia) which are not so contaminated as primary producers (Table III). Laboratory experiments andin situ measurements in seawater and freshwater environments reported in the literature confirm a general tendency to a decreasing of radiocobalt concentrations as a function of trophic level.     

苏云金芽胞杆菌cry1A基因启动子上激区不同位点突变对BtI—la …

利用苏云金芽胞杆菌ｃｒｙ１Ａ启动子上游区的不同突变体,观测对ＢｔＩ－ｌａｃＺ融合基因表达的影响。结果发现,突变上游弯曲区,导致ＢｔＩ－ｌａｃＺ在菌标８０－２１中的酶活性大幅度下降,均比未突变的上游区降低２－２．５倍。而在菌株ＨＤ１３３－５中却出现相反的结果,即上游弯曲区的突变导致ＢｔＩ－ｌａｃＺ的表达比未突变体增高。如果同时突变弯曲区和反射重复区,则ＢｔＩ－ｌａｃＺ在菌 表达增强或下降的幅度大大减     

Reduced breeding success in white-tailed eagles at Smøla windfarm,western Norway,is caused by mortality and displacement

Climate change scenarios and efforts to reduce CO₂ emissions have increased the focus on wind power and other renewable energy sources. Despite producing “clean” electricity, windfarms do have impacts on the environment. We studied the impact from a coastal windfarm on the breeding success of white-tailed eagles (Haliaeetus albicilla) at Smøla, western Norway by means of a BACI (before–after–control–impact) approach. The objective was to compare pre- and post-construction breeding success. A 10 year dataset from 47 eagle territories were analyzed using a generalized linear mixed model. Successful breeding was used as a response variable, while distance to turbines, distance to roads and before/after turbine construction were used as predictors. There was a significant effect of the interaction between time period and distance to turbines, showing that territories within 500 m from the turbines in the post-construction period experienced significantly lower breeding success than the same territories before construction. We found that this effect was most likely due to territories being vacated. The results emphasize the importance of using a BACI approach when assessing possible effects from wind-power production on breeding birds, especially for species breeding at low densities. It also emphasizes the importance of conducting thorough pre-construction studies on vulnerable bird species.     

copper,lead and zinc distribution in soils and sediments of the south-western coast of the río de la plata estuary

Background, Aim and Scope.  The compositional study of suspended matter in water from rivers of different latitudes and climates has revealed that the fine fraction reflects both substrate lithology from source areas or topsoil composition along the course. Metal distribution patterns are also strongly related to the clay mineral fate in fluvial aquatic systems. For the particular case of the coastal area of the Río de la Plata estuary in South America, previous studies have, on the one hand, focused on the analysis of distribution patterns of heavy metals in bottom river sediments and, on the other hand, on the assessment of metal contents in topsoils. The present study was conducted to evaluate the Cu, Pb and Zn distribution in soils and sediments from four drainage basins crossing two differentiated geomorphologic units composed of unconsolidated materials and to understand the metal behaviour. Methods  Data used included the existent, self-produced soil and sediment data sets (grain size, organic matter and Cu, Pb and Zn contents from 124 samples). Analyses were performed by using standardised methods: grain size analysis by sieving and settling; organic matter content based on the reduction of dichromate ion followed by titration; metal content by atomic absorption spectrophotometry following acid digestion. Results and Discussion. The average (% w/w) clay and organic matter content were 45.9 ± 17.1 and 1.5 ± 1.7 for sediments and 32.0 ± 19.8, and 7.5 ± 7.6 for soils, respectively. The raw mean metal concentrations (mg-kg^-1 dry weight) for sediments and soils were: Cu: 28.02 ± 27.28, 32.08 ± 21.64; Pb: 32.08 ± 46.94, 68.44 ± 69.25 and Zn: 83.09 ± 150.33, 118.22 ± 74.20, respectively. A good correlation for each clay-normalised metal concentration was found between soil and sediments using regression analysis considering average data for each basin sampling site (r > 0.89, p < 0.05). A comparison between metal concentration levels taking into account geomorphologic units by a t independent sample test showed significant differences for the normalised soil-sediment metal data (p < 0.001), responding to differences in grain size, clay mineralogy, organic matter and neoformed Fe-Mn oxide composition. Conclusion, Recommendation and Outlook  A clear parenthood between the topsoils and the bottom sediments in the study area was found. The Argiudolls from the inner zone are frequently affected by rainwater erosion, which washes the fine materials with sorbed metals and carries them to the streams. These watercourses reach the flat coastal plain, where soil flooding and bottom sediment depositional processes predominate. Here, both soils and bottom sediments are enriched in clay, organic matter and metals. The topography and lithology, under the environmental conditions of a temperate and humid climate control the fate of metals within these small basins. The influence of the physical media on the distribution and fate of pollutants should not be minimised in the understanding of the governing processes from natural systems.     

Serum ferritin, cardiovascular risk factors and ischaemic heart diseases: a prospective analysis in the SU.VI.MAX (SUpplementation en VItamines et Minéraux AntioXydants) cohort

BACKGROUND: Iron has been suggested to play a role in the development of cardiovascular disease (CVD) through its pro-oxidant properties. However, epidemiological studies on iron status and the risk of CVD have yielded conflicting results. We therefore carried out a prospective study to evaluate the relationship between iron status and CVD in a middle-aged French population. METHODS: In total, 9917 subjects (3223 men aged 45-60 years and 6694 women aged 35-60 years) included in the SU.VI.MAX (SUpplementation en VItamines et Minéraux AntioXydants) cohort were followed prospectively for 7.5 years. All cases of ischaemic heart disease (IHD) were identified and validated. CVD risk factors, haemoglobin and serum ferritin concentrations were measured at baseline. FINDINGS: Of men 4.3%, and of women 37.8%, presented at baseline a serum ferritin concentration <30 microg l(-1). During the follow-up, 187 subjects (148 men, 39 women) developed IHD. Serum ferritin was positively associated with total cholesterol, serum triglycerides, systolic and diastolic blood pressure, body mass index and haemoglobin. No linear association was found between serum ferritin and IHD risk in men or in women. CONCLUSION: Our data do not support a major role of iron status in the development of IHD in a healthy general population.