Inhibition of microorganisms involved in deterioration of an archaeological site by silver nanoparticles produced by a green synthesis method.

The Citadel, part of the pre-Hispanic city of Teotihuacan and listed as a World Heritage Site, harbors irreplaceable archaeological walls and murals. This city was abandoned by the 7th century and its potential deterioration represents a noteworthy loss of the world's cultural heritage. This research consisted of isolation and identification of bacteria and fungi contributing to this deterioration from walls of a pre-Hispanic city. In addition, silver nanoparticles (AgNP) produced, using a green synthesis method, were tested as potential inhibitors of microbes. AgNP of different sizes and concentrations were tested using in situ assays. Leaf aqueous extracts from two plants species (Foeniculum vulgare and Tecoma stans) and two extraction procedures were used in the NP synthesis. The potential of AgNP as preventive/corrective treatments to protect stucco materials from biodeterioration, as well as the microbial inhibition on three stone materials (stucco, basalt and calcite) was analyzed. Twenty-three bacterial species belonging to eight genera and fourteen fungal species belonging to seven genera were isolated from colored stains, patinas and biofilms produced on the surfaces of archaeological walls from the pre-Hispanic city, Teotihuacan. AgNP from F. vulgare were more effective for in vitro microbial growth inhibition than those from T. stans. Bacteria were less sensitive to AgNP than fungi; however, sensitivity mainly depended on the microbial strain and the plant extract used to prepare AgNP. The use of AgNP as a preventive or corrective treatment to decrease microbial colonization in three kinds of stone used in historical walls was successful. Calcite was more colonized by Alternaria alternata, but less by Pectobacterium carotovorum. This is the first study at different scales (in vitro and tests on different stone types) of inhibition of biodeterioration-causing microorganisms isolated from an archaeological site by green synthesized AgNP.

Potential of castor bean (Ricinus communis L.) for phytoremediation of mine tailings and oil production.

Bioenergy production combined with phytoremediation has been suggested to help in solving two critical world problems: the gradual reduction of fossil fuels and soil contamination. The aim of this research was to investigate the potential for the use of Ricinus communis L. (castor oil plant) as an energy crop and plant species to remediate metal-polluted sites. This study was performed in mine tailings containing high concentrations of Cu, Zn, Mn, Pb and Cd. Physico-chemical characterization, total, DTPA-extractable and water-soluble metals in rhizospheric tailings heap samples were carried. Metal concentrations in plant tissues and translocation factors (TFs) were also determined. The Ricinus seed-oil content was high between 41 and 64%, seeds from San Francisco site 6 had the highest oil content, while these from site 7 had the lowest. No trend between oil yield vs seed origin site was observed. Seed-oil content was negatively correlated with root concentration of Cu, Zn, Pb and Cd, but no correlation was observed with the extractable-metals. According to its shoot metal concentrations and TFs, castor bean is not a metal accumulator plant. This primary colonizing plant is well suited to cope with the local toxic conditions and can be useful for the stabilization of these residues, and for then decreasing metal bioavailability, dispersion and human health risks on these barren tailings heaps and in the surrounding area. Our work is the first report regarding combined oil production and a phytostabilization role for Ricinus plants in metal mine tailings and may give a new value to suitable metal-polluted areas.

Feeding of tropical trees and shrub foliages as a strategy to reduce ruminal methanogenesis: studies conducted in Cuba.

The aim of this paper was to present the main results obtained in Cuba on the effects of feeding tropical trees and shrubs on rumen methanogenesis in animals fed with low quality fibrous diets. More than 20 tree and shrub foliages were screened for phytochemicals and analyzed for chemical constituents. From these samples, seven promising plants (Samanea saman, Albizia lebbeck, Tithonia diversifolia, Leucaena leucocephala, Trichantera gigantea, Sapindus saponaria, and Morus alba) were evaluated for methane reduction using an in vitro rumen fermentation system. Results indicated that the inclusion levels of 25% of Sapindo, Morus, or Trichantera foliages in the foliages/grass mixtures (grass being Pennisetum purpureum) reduced (P < 0.01) methane production in vitro when compared to Pennisetum alone (17.0, 19.1, and 18.0 versus 26.2 mL CH(4)/g fermented dry matter, respectively). It was demonstrated that S. saman, A. lebbeck, or T. diversifolia accession 23 foliages when mixed at the rate of 30% in Cynodon nlemfuensis grass produced lower methane compared to the grass alone. Inclusion levels of 15% and 25% of a ruminal activator supplement containing 29% of L. leucocehala foliage meal reduced methane by 37% and 42% when compared to the treatment without supplementation. In vivo experiment with sheep showed that inclusion of 27% of L. leucocephala in the diet increased the DM intake but did not show significant difference in methane production compared to control diet without this foliage. The results of these experiments suggest that the feeding of tropical tree and shrub foliages could be an attractive strategy for reduction of ruminal methanogenesis from animals fed with low-quality forage diets and for improving their productivity.

Effects of calcium supplementation on fetal growth in mothers with deficient calcium intake: a randomised controlled trial.

Calcium supplementation in mothers with low calcium intake has been of interest recently because of its association with optimal fetal growth and improved pre-eclampsia-related outcomes. While the effects of calcium supplementation have demonstrated benefits in prolonging gestation and subsequently improving birthweight, no specific studies have identified the longitudinal effects of supplementation on fetal growth in utero. Data were analysed in the context of the World Health Organization trial of calcium supplementation in calcium-deficient women. Five hundred and ten healthy, primiparous pregnant Argentinean women were randomised (at <20 weeks gestation) to either placebo (n = 230) or calcium supplements (1500 mg calcium/day in 3 divided doses; n = 231). Growth parameters in utero were assessed with serial ultrasound scans. Birthweight, length, head, abdominal and thigh circumferences were recorded at delivery. No differences were found in fetal biometric measurements recorded at 20, 24, 28, 32 and 36 weeks gestation between fetuses of women who were supplemented with calcium and those who were not. Similarly, neonatal characteristics and anthropometric measurements recorded at delivery were comparable in both groups. We conclude that calcium supplementation of 1500 mg calcium/day in pregnant women with low calcium intake does not appear to impact on fetal somatic or skeletal growth.

Effects of calcium supplementation on uteroplacental and fetoplacental blood flow in low-calcium-intake mothers: a randomized controlled trial.

OBJECTIVE: We postulated that calcium supplementation of calcium-deficient pregnant women would lower vascular resistance in uteroplacental and fetoplacental circulations. STUDY DESIGN: Pulsatility index (PI) and resistance index (RI) (uterine and umbilical arteries) and presence of bilateral uterine artery diastolic notching were assessed by Doppler ultrasound between 20-36 weeks' gestation in 510 healthy, nulliparous Argentinean women with deficient calcium intake in a randomized, placebo-controlled, double-blinded trial. RESULTS: Average umbilical and uterine artery RI and PI tended to be lower in the supplemented group at each study week. Differences became statistically significant for umbilical artery RI and PI from 32 and 36 weeks, respectively. Estimated probabilities of bilateral uterine artery diastolic notching trended toward lower values in calcium-supplemented women. CONCLUSION: Calcium supplementation of pregnant women with deficient calcium intake may affect uteroplacental and fetoplacental blood flow by preserving the vasodilation of normal gestation.

Plant and fungal biodiversity from metal mine wastes under remediation at Zimapan, Hidalgo, Mexico.

Plant establishment, presence of arbuscular mycorrhizal fungi (AMF) and other rhizospheric fungi were studied in mine wastes from Zimapan, Hidalgo state, Mexico, using a holistic approach. Two long-term afforested and three non-afforested mine tailings were included in this research. Fifty-six plant species belonging to 29 families were successfully established on the afforested sites, while unmanaged tailings had only a few native plant species colonizing the surrounding soils. Almost all plant roots collected were associated to AMF in these sites. The genus Glomus was the most abundant AMF species found in their rhizosphere; however, the Acaulospora genus was also observed. Other rhizospheric fungi were identified by 18S rDNA sequencing analysis. Their role in these substrates, i.e. biocontrol, pollutant- and organic matter-degradation, and aides that increase plant metal tolerance is discussed. Our results advance the understanding of fungal diversity in sites polluted with metals and present alternative plants for remediation use.