Heavy Metals in Soil, Crops and Grass as a Source of Human Exposure in the Former Mining Areas (6 pp)

Background, Aim and Scope   In the former mining area of Northern France, the number of diseases (cancers, malformations, backwardness...) is about ten times above the national average. Environmental surveys conducted by the Ministry of Health have showed that more than 10% of children living around a lead smelter located in this area had lead levels higher than 100 μg L-1 of blood (25% in the closest city). Two main factors contribute to the population exposure: the ingestion of plants produced in the contaminated area, and also the ingestion or the inhalation of contaminated dust or soil. It is usually known that these particles are key routes of exposure to lead for younger children, in particular via hand-to-mouth transfer. For a better understanding of this problem, researchers investigated different exposure sources like soil and vegetable contamination. Materials and Methods: All these parameters that contribute to the assessment of environmental and health risks of metal contamination have been measured. About 170 composite samples of soils around the smelter or from reference areas have been analysed, mainly from fields (70), kitchen gardens (60) and lawns (38). Total contents of Cd and Pd were measured in the organo-mineral layer (0-25cm) of soils. Composite grass samples were also taken on the lawns. Crops and vegetables were sampled from fields and kitchen gardens and then, parts of the plant intended only for consumption were washed and analysed. Results: For the organo-mineral horizon of the studied sites and located in various environmental contexts (contaminated or reference), we found a very broad range of metal concentrations. Generally, the data showed a strong variability of the physicochemical parameters of the urban soils (kitchen gardens, lawns), in particular with regard to lead. This work showed that cultivated plants (agricultural or kitchen garden) or lawn grass are also significantly contaminated by heavy metals, especially lawn grasses, cereal grains (wheat, barley) and lettuces sampled around the smelter. Moreover, the proportion of lead present on lawn grasses could reach 50% of the total contamination of the plants because of the deposition of contaminated dust. Discussion: The values of pollution in agricultural field and kitchen garden soils located near the smelter were respectively about 20 and 30 times above the agricultural regional reference values, probably due to the atmospheric emissions from a smelter that significantly increases the concentrations of metals in the upper horizons of the neighbouring soils. This pollution results in a high level of contamination of plants grown of these soils. Conclusions: The results showed that heavy metals in soils, particles (dust and soil) or plants of kitchen gardens, lawns or playgrounds could be potentially transferable to the users, and in particular to young children, and could then contribute, to a considerable share, to the exposure of the population living in a contaminated area around a smelter brought about through inhalation, direct ingestion of particles or consumption of plants. Recommendations and Perspectives: These results highlight that the consumption of home-grown vegetables can constitute a risk of exposure, in particular for cadmium, and especially in children. This work also underlined the role of the contaminated soil particles in the Pb contamination of the human food chains and their environment. Because of the complexity of the various methods of population exposure, it will be necessary to complete the data base, in partucular in urban areas. The main objective of this future work will be to relate the degree of environmental contamination with the lead level in child bood, and to integrate other environmental compartments like outdoor and indoor dust of the dwellings into the model of pathway exposure.     

Microassay for rapid screening of alpha-amylase activity

A microassay was developed for measuring the activity of alpha-amylases in the nanogram enzyme concentration range, based on the use of dye-labeled cross-linked starch as the substrate, and the release of soluble colored fragments formed in enzyme hydrolysis. Reaction conditions were optimized to generate a linear correlation between the increase in absorbance and a reaction time of 0-10 min, as well as enzyme concentrations in the range of 0-50 ng. A standard curve for the conversion of absorbance to enzyme activity units was constructed. The protocol developed was applied to monitoring the production of ultralow concentrations of recombinant barley alpha-amylase in yeast cells.     

A 12-month survey of gastrointestinal helminth infections of cervids kept in two zoos in Belgium.

Infections with helminths are a major health issue in captive and wild deer. In this study, fecal egg count patterns and clinical signs associated with gastrointestinal nematodes were assessed for 12 mo in nine cervid herds kept under different husbandry conditions at two sites. At site 1, an urban zoo, fecal egg counts remained low and no clinical signs of parasitic gastroenteritis were seen in the herds of fallow deer (Dama dama), Dybowski's deer (Cervus nippon dybowski), pudu (Pudu pudu), and reindeer (Rangifer tarandus tarandus). Helminth infection at this site may have been successfully prevented by daily dung removal of the small sandy-soil enclosures, and applying routine anthelmintic treatment was not justified. At site 2, a wild animal park, involved species were red deer (Cervus elaphus hippelaphus), Nelson's elk (Cervus elaphus nelsoni), Père David's deer (Elaphurus davidianus), European elk (Alces alces alces), and reindeer (Rangifer tarandus tarandus). Nematode eggs were frequently encountered in herds of red deer, Nelson's elk, and European elk, which were kept on larger, grassy enclosures that were irregularly cleaned. The trimodal pattern of fecal egg counts in herds from the wild animal park, consisting of a small spring rise in June, a peak in October, and a small rise in February, indicates that infective larvae on pastures are the main source of infection. In addition, routine anthelmintic treatment with fenbendazole in April and July limited egg shedding, but reinfection rapidly occurred. In two European elk and one reindeer, increasing fecal egg counts were associated with loss of fecal consistency and reduced appetite. Three genera and three species of nematodes were recovered at necropsy of one red deer and three Nelson's elk: Spiculopteragia spiculoptera, Trichostrongylus spp., Nematodirus filicollis, Capillaria spp., Oesophagostomum radiatum, and Trichuris spp., with total worm counts between 950 and 8,700.     

A field evaluation of serological and cellular diagnostic tests for bovine tuberculosis.

This paper describes the field evaluation of a serological test and a new in vitro assay for cell-mediated reactivity for the diagnosis of bovine tuberculosis. The use of a Mycobacterium bovis-specific antigen (MPB-70) in an ELISA to test the serological response to tuberculosis infection resulted in a specificity of 96.4% and a sensitivity of 18.1%. The most favourable results were obtained with the interferon gamma (IFN-gamma) assay which had a sensitivity of 81.8% and a specificity of 99.1%. Respective figures for the single intradermal tuberculin test were 68.1% and 96.7%. The use of MPB-70 as the antigen in the IFN-gamma assay reduced the sensitivity of this assay, without producing any useful increase in specificity. The IFN-gamma assay was also demonstrated to be a practical diagnostic test for use with large groups of cattle.     

Subcellular distribution of beta-carotene, retinol, and alpha-tocopherol in porcine lymphocytes after a single injection of beta-carotene.

The subcellular distribution of beta-carotene, retinol, and alpha-tocopherol in lymphocytes was studied in pigs (50 to 55 kg) injected once with 0, 20, or 40 mg of beta-carotene. Blood was sampled at 0, 24, 48, and 72 h postinjection. Plasma beta-carotene in treated pigs peaked at 24 h and decreased rapidly thereafter. Beta-carotene was found in all subcellular fractions of lymphocytes. Concentrations in nuclei mirrored changes in plasma. However, beta-carotene in mitochondria and cytosol peaked at 24 h, whereas that in microsomes peaked at 48 h. Concentrations in the latter three subcellular fractions remained high at 48 and 72 h even though plasma beta-carotene had decreased to very low concentrations. Peak concentrations of beta-carotene were highest in the nuclei, intermediate in the mitochondria and microsomes, and lowest in the cytosol. Treatment did not influence concentrations of retinol or alpha-tocopherol in the various subcellular fractions. These data provide more compelling evidence for the possible role of beta-carotene in lymphocytes.     

Heterothallism in Plasmopara viticola

Sexuality in the oomycete Plasmopara viticola , the causal agent of grapevine downy mildew, was studied using isolates from five populations from North America and Europe. Leaf discs of Vitis vinifera cv. 'Chardonnay' were inoculated with either individual single-sporangiophore isolates, or in all possible pairwise combinations of 25 isolates from New York State, USA. The occurrence of oospores in leaf discs indicated that the pathogen was heterothallic with two mating types, P1 and P2 in a ratio of 11 : 14 for this population. Heterothallism was confirmed when three representative isolates of each mating type from New York were coinoculated with each of 40 isolates from populations of P. viticola from Michigan, Missouri (USA), Germany and Italy. For each isolate tested, oospores formed with either test isolates of P1 or test isolates of P2 mating types, indicating that the isolates were exclusively P1 or P2 only. For these same isolates, no oospores formed as a result of self-crosses. The ratio of P1 : P2 mating types for all isolates in the study was 27 : 38, statistically equivalent to a 1 : 1 ratio according to χ² analysis ( P  = 0·68).     

Growth performance and carcass composition of lambs infused for 28 days with a growth hormone-releasing factor analogue.

A human growth hormone-releasing factor analogue, [DesNH2Tyr1,D-Ala2,Ala15]hGRF(1-29)NH2 (GRF-A), was infused s.c. into lambs for 28 d to determine its effects on growth performance and carcass composition. Twenty crossbred wethers weighing 47.0 +/- .5 kg were implanted with 7-d osmotic minipumps at weekly intervals. Minipumps contained either vehicle (dimethyl sulfoxide:H2O, 1:1) or GRF-A, released at a rate of 208 pmol (or .7 micrograms).h-1.kg-1. During the infusion period, plasma GH levels were increased (P less than .01) in GRF-A-treated wethers compared with control wethers (15.0 vs 9.3 ng/ml) and were higher on days that closely followed minipump implantation. Plasma IGF-I and hepatic IGF-I RNA concentrations were similar in lambs of both groups. Analogue treatment improved feed conversion (4.9 vs 5.8 kg dry matter/kg gain, P less than .05), increased average daily gain (.35 vs .30 kg, P = .05) and had no effect on feed intake, wool growth and body, carcass, selected organ and pituitary weights. Carcasses from GRF-A-infused lambs had less adjusted fat depth, a lower percentage of fat and a higher percentage of protein (P less than .05) than carcasses from control lambs. Magnitude of most effects of GRF-A on carcass measurements were correlated with the mean GH level that a lamb had during the infusion period. In conclusion, s.c. infusion of GRF-A improved feed utilization and altered carcass composition of feeder lambs in a relatively short period of time (28 d).     

Estimates of within family genetic variability for clonal selection in oil palm

Within family genetic and environmental variabilities in oil palm dura (D) ×pisifera (P) hybrid progenies were estimated from a D × P progeny test trial, a clonal trial and a clonal cum D × P progeny test trial and with the objective of examining the efficiency of selecting source palms (ortets) within family for clonal propagation. The clones were derived from seedling embryos or seedlings that were progeny reproductions of families proven in the first trial. The progenies in the second trial represented the source families of two sets of clones planted in the same trial. Estimates were obtained from: between and within family variance components; between and within clone variance components; and difference between pooled within family variance and pooled within clone variance. Estimates were generally similar with the different methods used. Within family genetic variabilities were generally low in progenies derived from more inbred parents especially in bunch and oil yields. In progenies from more outbred or variable parents, within family genetic variabilities were relatively higher particularly for oil to bunch and palm height; nevertheless environmental variabilities predominated. The low efficiency of within family palm or ortet selection for clone production and the need for repeated clonal tests over time and space to identify outstanding clones are stressed and the implications to commercial clonal propagation of oil palm discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

Intracellular mechanisms mediating gonadotropin and growth hormone release in the goldfish,Carassius auratus

Evidence for the involvement of Ca²⁺, protein kinase C, cAMP, and arachidonic acid metabolism in mediating gonadotropin (GTH) and growth hormone (GH) release in the goldfish is reviewed. Models for the signal transduction pathways mediating GTH-releasing hormone (GnRH) and dopamine actions on GTH and GH secretion are postulated. A novel hypothesis that two GnRHs which bind to the same receptor type activate different transduction cascade in two different cell types (GTH vs. GH) as well as within the same cell type (GTH) is presented.

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Résumé Cette revue présente les données expérimentales démontrant l'implication de Ca⁺⁺, de la protéine kinase C et du métabolismes de l'acide arachidonique dans les mécanismes régulant la sécrétion des hormones gonadotrope (GTH) et de croissance (GH). Des modèles de signaux de transduction de l'action de la gonadolibérine (GnRH) et de la dopamine sur la sécrétion de GTH et de GH sont proposés. Les deux GnRHs existant chez le poisson rouge pourraient se lier au même type de récepteur et activer différentes voies de transduction dans deux différents types cellulaires (GTH vs. GH) ou dans un seul type (GTH).

     

黄麻(corchorus olitorius L.)花青素的性状遗传及其表现的影响因素

1986～1988年对长果黄麻(Corchorus olitorius L.)花青素的性状遗传及其表现作了研究。结果表明,长果黄麻花青素遗传受一对等位基因控制。花青素的合成需要光照条件,但合成的速度和含量则决定于糖浓度。光照强弱和供氮水平对花青素含量的影响,是通过对糖浓度的影响而起作用。合成花青素的细胞可能与合成叶绿素有关。花青素在体内可以转移。