Maria Duarte-Gardea

Interaction of Nanoparticles with Edible Plants and Their Possible Implications in the Food Chain

The uptake, bioaccumulation, biotransformation, and risks of nanomaterials (NMs) for food crops are still not well understood. Very few NMs and plant species have been studied, mainly at the very early growth stages of the plants. Most of the studies, except one with multiwalled carbon nanotubes performed on the model plant Arabidopsis thaliana and another with ZnO nanoparticles (NPs) on ryegrass, reported the effect of NMs on seed germination or 15-day-old seedlings. Very few references describe the biotransformation of NMs in food crops, and the possible transmission of the NMs to the next generation of plants exposed to NMs is unknown. The possible biomagnification of NPs in the food chain is also unknown.

Monitoring the environmental effects of CeO2 and ZnO nanoparticles through the life cycle of corn (Zea mays) plants and in situ μ-XRF mapping of nutrients in kernels

Information about changes in physiological and agronomic parameters through the life cycle of plants exposed to engineered nanoparticles (NPs) is scarce. In this study, corn (Zea mays) plants were cultivated to full maturity in soil amended with either nCeO2 or nZnO at 0, 400, and 800 mg/kg. Gas exchange was monitored every 10 days, and at harvest, bioaccumulation of Ce and Zn in tissues was determined by ICP-OES/MS. The effects of NPs exposure on nutrient concentration and distribution in ears were also evaluated by ICP-OES and μ-XRF. Results showed that nCeO2 at both concentrations did not impact gas exchange in leaves at any growth stage, while nZnO at 800 mg/kg reduced net photosynthesis by 12%, stomatal conductance by 15%, and relative chlorophyll content by 10% at day 20. Yield was reduced by 38% with nCeO2 and by 49% with nZnO. Importantly, μ-XRF mapping showed that nCeO2 changed the allocation of calcium in kernels, compared to controls. In nCeO2 treated plants, Cu, K, Mn, and Zn were mainly localized at the insertion of kernels into cobs, but Ca and Fe were distributed in other parts of the kernels. Results showed that nCeO2 and nZnO reduced corn yield and altered quality of corn.

Use of hop (Humulus lupulus) agricultural by-products for the reduction of aqueous lead(II) environmental health hazards

The agricultural by-products of the hop plant (Humulus lupulus L.) were investigated to determine their potential for use in the removal of heavy lead(II) ions from contaminated aqueous solutions. Separate batch laboratory experiments were performed to establish the optimal binding pH, time exposures, and capacity of the metal adsorption for lead(II) ions by dried and ground hop leaves and stems biomass. Results from these studies have shown a pH dependent binding trend from pH 2-6, with optimum binding occurring around pH 5.0. Time dependency experiments showed a rapid adsorption of lead(II) ions within the first 5 min of contact. Binding capacity experiments demonstrated that 74.2mg of lead(II) were bound per gram of leaf biomass. Similarly overall capacity was seen for the leaves and stems. Desorption of 99% of the bound lead(II) ions was achieved by exposing the metal laden biomass to 0.5M sodium citrate. Further experiments were performed with silica-immobilized hop tissues to determine the lead(II) binding ability under flow conditions. Comparison studies were performed with ion-exchange resins to evaluate the binding ability and to gain further insight into the metal binding mechanism. X-ray absorption spectroscopy experiments were also utilized to gain further insight into the possible lead(II) binding mechanism by the hop plant tissue. Results from these studies indicate that carboxyl ligands are involved in the binding of lead(II) from aqueous solution. These findings show that the use of hop agricultural waste products may be a viable alternative, for the removal and recovery of aqueous lead(II) ions from contaminated waters.

Alfalfa growth promotion by bacteria grown under iron limiting conditions

Abstract This investigation has been conducted to compare and contrast the impact of 18 potentially plant growth-promoting bacterial strains, cultured in rich and iron-deficient minimal media, on alfalfa seed germination and seedling vigor. Our results showed that seed germination was improved by all of the bacterial strains grown in iron-deficient minimal medium. We also found that all the seeds inoculated with the bacterial strains grown in iron-deficient minimal medium produced seedlings with larger roots (55–66 mm) than the roots of uninoculated control plants (54.9 mm). Furthermore, most of the strains cultivated in iron-deficient minimal medium generated seedlings with larger roots than those seeds inoculated with microbial cells grown in iron-rich medium (37–59 mm). Overall, seeds inoculated with the strain U cultivated in iron-deficient minimal medium gave rise to plantlets with the greatest length (81 mm). On the other hand, seeds inoculated with bacterial cells grown under iron-rich media show significantly higher stem and root dry weight, which is an indication of the influence of the growth conditions on the plant growth-promoting ability of these microorganisms.

Potential of Chilopsis linearis for gold phytomining: using XAS to determine gold reduction and nanoparticle formation within plant tissues.

This study reports on the capability of the desert plant Chilopsis linearis (Cav.) Sweet (desert willow) to uptake gold (Au) from gold-enriched media at different plant-growth stages. Plants were exposed to 20, 40, 80, 160, and 320 mg Au L−1 in agar-based growing media for 13, 18, 23, and 35 d. The Au content and oxidation state of Au in the plants were determined using an inductively coupled plasma/optical emission spectrometer (ICP/OES) and X-ray absorption spectroscopy (XAS), respectively. Gold concentrations ranging from 20 to 80 mg Au L−1 did not significantly affect Chilopsis linearis plant growth. The concentration of gold in the plants increased as the age of the plant increased. The Au concentrations in leaves for the 20, 40, 80, and 160 mg Au L−1 treatments were 32, 60, 62, and 179 mg Au kg−1 dry weight mass, respectively, demonstrating the gold uptake capability of desert willow. The XAS data indicated that desert willow produced gold nanoparticles within plant tissues. Plants exposed to 160 mg Au L−1 formed nanoparticles that averaged approximately 8, 35, and 18 Å in root, stem, and leaves, respectively. It was observed that the average size of the Au nanoparticles formed by the plants is related to the total Au concentration in tissues and their location in the plant

A critical review: early life nutrition and prenatal programming for adult disease

AIM AND OBJECTIVE To present the evidence in relation to early life nutrition and foetal programming for adult disease. BACKGROUND Epigenetics is a new and growing area of study investigating the impact of the intrauterine environment on the lifelong health of individuals. DESIGN Discursive paper. METHOD Searches were conducted in a range of electronic health databases. Hand searches located additional articles for review. Maternal search terms included: pregnancy; nutrition; diet; obesity; over nutrition; under nutrition. Offspring related search terms included: macrosomia; intrauterine growth restriction; epigenetics; foetal programming; childhood obesity; adolescent obesity; adolescent type 2 diabetes. DISCUSSION Results indicate that foetal programming for adult disease occurs in response to particular insults during vulnerable developmental periods. Four main areas of foetal exposure were identified in this review: (1) under nutrition; (2) over nutrition; (3) gestational diabetes mellitus; and (4) infant catch-up growth. Numerous studies also described the trans-generational nature of foetal programming. CONCLUSIONS Overall, foetal exposure to excess or insufficient nutrition during vulnerable developmental periods appears to result in a lifelong predisposition to obesity and adult disease, such as type 2 diabetes and cardiac disease. For the infant who has been undernourished during early life, a predisposition to renal disease also occurs. RELEVANCE TO CLINICAL PRACTICE Pregnancy is a time when women are engaged in health systems and are receptive to health messages. These factors suggest that pregnancy may be an optimal time for dietary education and intervention. There is a particular need for education on healthy diet and for interventions which aim to limit over consumption of calories.

Effect of indole-3-acetic acid, kinetin, and ethylenediaminetetraacetic acid on plant growth and uptake and translocation of lead, micronutrients, and macronutrients in alfalfa plants.

Alfalfa plants germinated and grown for 15 d in soil containing 80 mg Pb kg−1 were treated with ethylenediaminetetraacetic acid (EDTA) at 0.8 mM and indole-3-acetic acid-kinetin (IAA-KN) at 100 μM. Fifteen days after the treatment application, the concentration of lead (Pb), macronutrients, and micronutrients was determined using inductively coupled plasma/optical emission spectroscopy. The chlorophyll content and plant growth were also measured. Roots of plants exposed to Pb alone, Pb–EDTA, and Pb–EDTA-IAA-KN had 160, 140, and 150 mg Pb kg−1 DW, respectively. Pb was not detected in the stems of plants exposed to Pb alone; however, stems of plants treated with EDTA and EDTA–IAA-KN had 78 and 142 mg Pb kg−1 DW, respectively. While the Pb concentration in leaves of plants treated with EDTA and EDTA–IAA-KN was 92 and 127 mg kg−1 DW, respectively. In addition, EDTA and EDTA–IAA-KN significantly increased the translocation of zinc and manganese to leaves. The x-ray absorption spectroscopic studies demonstrated that Pb(II) was transported from roots to leaves without a change in the oxidation state.

Overweight and Obese Humans Overeat Away from Home

The built environment has been implicated in the development of the epidemic of obesity. We investigated the differences in the meal patterns of normal weight vs. overweight/obese individuals occurring at home vs. other locations. The location of meals and their size in free-living participants were continuously recorded for 7 consecutive days. Study 1: 81 males and 84 females recorded their intake in 7-day diet diaries and wore a belt that contained a GPS Logger to record their location continuously for 7 consecutive days. Study 2: 388 males and 621 females recorded their intake in diet diaries for 7 consecutive days. In both studies, compared to eating at home, overweight/obese participants ate larger meals away from home in both restaurants and other locations than normal weight participants. Overweight/obese individuals appear to be more responsive to environmental cues for eating away from home. This suggests that the influence of the built environment on the intake of overweight/obese individuals may contribute to the obesity epidemic.

Role of ethylenediaminetetraacetic acid on lead uptake and translocation by tumbleweed (Salsola kali L.)

Tumbleweed plants (Salsola kali L.) grown in agar and liquid media demonstrated a high capacity to accumulate Pb in their different parts without affecting biomass. Whereas shoot elongation and biomass were not significantly affected by high tissue concentrations of Pb, root growth was significantly affected relative to controls. Roots, stems, and leaves demonstrated Pb concentrations of 31,000, 5,500, and 2,100 mg/kg dry weight, respectively, when plants were grown in the agar medium containing 80 mg Pb/L. Application of ethylenediaminetetraacetic acid (EDTA) to Pb-contaminated media dramatically reduced the total acquisition of Pb from both types of media. However, EDTA significantly increased the translocation of Pb from roots to the aerial parts, as evidenced by a multifold increase (23- and 155-fold for agar and liquid media, respectively) in the translocation concentration factor. The concentration of the antioxidant thiol compounds significantly increased (p < 0.05) in plants grown with uncomplexed Pb treatments relative to control plants. Scanning-electron microscopy and electron dispersive x-ray spectroscopic evaluation of leaf samples demonstrated an interesting pattern of Pb translocation in the presence or absence of EDTA. Large Pb crystals were found across the leaf tissues (palisade, spongy parenchyma, and conducting tissues) in the absence of EDTA. Lead nanoparticles also were seen when plants were grown in Pb-EDTA solution. Ultramicroscopic features of tumbleweed provide clear evidence for the unrestricted conduction of Pb from the root to the aerial parts, and this property makes the plant a good candidate for phytoremediation.

Oral versus vaginal misoprostol for labor induction.

OBJECTIVE To compare the safety and effectiveness of vaginal with oral misoprostol for induction of labor. METHODS A total of 107 women with clinical indication for induction were randomly assigned to receive oral or vaginal misoprostol. Doses of 100 μg of oral or 25 μg of vaginal misoprostol were given every 3–4 hours. If cervical ripening or active labor did not occur, repeated doses of oral (100–200 μg) or vaginal (25–50 μg) were given until labor was established. RESULTS Fifty‐nine women received oral misoprostol, and 48 received vaginal administration. Delivery time was similar for the vaginal and oral arms (1074 ± 488 minutes versus 930 ± 454 minutes, P = .11). Parity was significantly different (P = .04) for the vaginal and oral groups. The cesarean delivery rate was similar for the vaginal and oral arms (17% versus 15%, P = .72). The number of medication administrations was consistent between groups. Birth weight was not different for patients in the control and treatment groups (vaginal 3281 ± 507 g versus oral 3359 ± 541 g, P = .44). Chorioamnionitis and tachysystole were comparable for the oral and vaginal groups. There was no statistical difference in neonatal outcomes. Similar proportions of infants were admitted to the well baby nursery and intermediate care nursery. CONCLUSION These findings indicate that, in a closely supervised hospital setting with adequate monitoring, oral misoprostol has the potential to induce labor as safely and effectively as its vaginal analogue.