Phytoremediation is an emerging technology that uses plants and their associated microbes to clean up pollutants from the soil, water, and air. In order to select the plant growth-promoting rhizobacteria(PGPR) for phytoremediation of heavy metal contamination, 60 bacterial strains were isolated from the rhizosphere of two endemic plants, Prosopis laevigata and Spharealcea angustifolia, in a heavy metal-contaminated zone in Mexico. These rhizobacterial strains were characterized for the growth at different pH and salinity, extracellular enzyme production, solubilization of phosphate, heavy metal resistance, and plant growth-promoting(PGP) traits, including production of siderophores and indol-3-acetic acid(IAA). Overall, the obtained rhizobacteria presented multiple PGP traits. These rhizobacteria were also resistant to high levels of heavy metals(including As as a metalloid)(up to 480 mmol L(-1)As(V), 24 mmol L(-1)Pb(Ⅱ), 21 mmol L(-1)Cu(Ⅱ), and 4.5 mmol L(-1)Zn(Ⅱ)). Seven rhizobacterial strains with the best PGP traits were identified as members of Alcaligenes, Bacillus, Curtobacterium, and Microbacterium, and were selected for further bioassay.The inoculation of Brassica nigra seeds with Microbacterium sp. CE3R2, Microbacterium sp. NE1R5, Curtobacterium sp. NM1R1,and Microbacterium sp. NM3E9 facilitated the root development; they significantly improved the B. nigra seed germination and root growth in the presence of heavy metals such as 2.2 mmol L(-1)Zn(Ⅱ). The rhizobacterial strains isolated in the present study had the potential to be used as efficient bioinoculants in phytorremediation of soils contaminated with multiple heavy metals. 相似文献
1. The objective of this study was to evaluate the ability of Campylobacter jejuni to penetrate and colonise eggs from specific-pathogen-free (SPF) and heavy breeder hens, and to determine its effects on the viability of SPF embryos.
2. We detected C. jejuni in 10% of breeder hens and 20% of SPF eggs, which demonstrates the ability of the bacteria to go through the pores of eggs and contaminate the vitellus after 3?h of contact. These results indicate that there is a risk of contamination under commercial production conditions, where, after oviposition, there is contact between the egg and organic material such as faeces and blood.
3. We observed that in 80% of SPF eggs analysed, C. jejuni survived the 21-d incubation period. This positive result suggests that this microorganism was also responsible for early embryonic mortality.
4. The ability of C. jejuni to penetrate the eggs in this study suggests that serious problems may occur under natural field conditions, which may cause significant problems for producers. 相似文献
Crude extracts and fractions of Bertholletia excelsa stem barks were tested for trypanocidal activity. Acetone and methanol extracts showed significant in vitro trypanocidal activity against trypomastigote form of Trypanosoma cruzi since in the concentration of 500 microg/ml, the parasites were reduced in 100% and 90.3% respectively, whereas the triterpene betulinic acid pure isolated from hexane extract presented 75.4%. 相似文献
The isolation of (+)-uleine (1) and (+)-demethoxyaspidospermine (2) from the bark of Plumeria lancifolia is reported along with (1)H- and (13)C-NMR data. 相似文献
Protein fractions from transgenic Bt and non-transgenic maize varieties, extracted by the Osborne solvent fraction procedure, were characterized for the first time by perfusion and monolithic RP-HPLC in very short analysis times. Albumins and globulins from different transgenic Bt maizes as well as from their non-transgenic isogenic varieties were eluted in four peaks using perfusion RP-HPLC, whereas prolamins and glutelins were separated in seven peaks. Monolithic RP-HPLC enabled the separation of maize proteins in a large number of peaks showing 6 and 10 main peaks for albumins and globulins, respectively. Prolamins migrated at retention times higher than 5 min as seven peaks, whereas glutelins were separated in three main peaks appearing at retention times higher than 6.0 min. Moreover, chromatograms of the whole protein extracts showed 8 and 11 components for perfusion and monolithic RP-HPLC, respectively. A comparison of the chromatograms of the whole protein extracts relative to transgenic and non-transgenic varieties evidenced quantitative differences on the percentages of area, mainly for peaks 2 and 3 by perfusion RP-HPLC and for peaks 3 and 7 by monolithic RP-HPLC. A discriminant analysis based on these proteic profiles was carried out to classify and predict transgenic Bt maize lines, achieving 100% correct classification using perfusion RP-HPLC. 相似文献
Relationships between volatile and nonvolatile compounds and the antioxidant capacity of coffee brews prepared from commercial conventional and torrefacto roasted coffees, employing commonly used doses and prepared by four brewing procedures (filter, plunger, mocha, and espresso machine) were assessed. Significant correlations between volatile Maillard reaction products and antioxidant capacity (measured by both 2,2-diphenyl-1-picrylhydrazyl radical and redox potential methods) were not observed. Highly positive correlations between browned compounds and caffeine with both antioxidant capacity parameters were reported. Principal component analysis allowed coffee brews separation according to coffee roasting processes (PC1) and brewing procedures (PC2), showing that in all cases coffee brews from torrefacto roasted coffee were more antioxidant that those extracted from conventional ones; also, coffee brews extracted by an espresso machine were more antioxidant than those extracted by mocha, plunger, and filter machines. 相似文献
The evolution of polyphenols of enological interest- monomeric anthocyanins, (+)-catechin, (-)-epicatechin, gallic acid, and trans-resveratrol-in the presence of oak wood was investigated in aging-model conditions. Disappearance kinetics showed that, except for gallic acid, all of the wine polyphenols tend to disappear from the model wine in presence of oak wood, to reach an equilibrium after 20 days of contact. At equilibrium, the higher disappearance rates were obtained for monomeric anthocyanins and trans-resveratrol with values of 20 and 50%, respectively. For monomeric anthocyanins, the rate of disappearance seemed to be independent of their nature. In order to evaluate the contribution of sorption to oak wood in the disappearance phenomena, sorption kinetics were determined for trans-resveratrol and malvidin-3-glucoside through the extraction and the quantification of the fraction sorbed to wood. These curves showed that the wood intake of trans-resveratrol and malvidin-3-glucoside followed a two-step behavior, with a higher rate during the first 2 days, likely due to a surface sorption mechanism, and then a slower rate to reach the equilibrium, which could be related to a diffusion mechanism. The comparison of disappeared and sorbed amounts at equilibrium showed that a minor part of the disappeared monomeric anthocyanins were sorbed by wood. In contrast, half of the concentration decrease of trans-resveratrol in wine finds its origin in a sorption mechanism by oak wood. Results in real wine show similar sorption kinetics. 相似文献
Various diagnostics techniques were compared for their ability to detect infectious laryngotracheitis (ILT) during an outbreak in chickens aged between 4 and 21 wk. Gross lesions ranged from excess mucus to accumulation of fibrinonecrotic exudate in the larynx and trachea. Syncytial cells with intranuclear inclusion bodies were found in sinus, conjunctiva, larynx, trachea, lung, and air sac. Virus isolation in chicken embryos was attempted in every case. Negative-stain electron microscopy detected herpesvirus in only 6% of the cases. Yet, isolation of ILT virus in the chorioallantoic membrane was presumed by histology in >20% of the samples and confirmed by fluorescent antibody (FA) in 35% of the embryos inoculated with conjunctivas or tracheas from affected birds. Overall, results from histology and FA tests were highly correlated. FA test has the advantage over histology of being diagnostically specific for ILT virus. Polymerase chain reaction was the most sensitive test and detected the viral DNA even in cases where histology and FA were negative. ILT virus DNA was quantified by real-time polymerase chain reaction (Re-Ti ILTV). Histologic and FA results from larynx and trachea were negative if the concentration of the viral DNA was < or =4 of log10. A viral DNA concentration higher than log10 4, as determined by Re-Ti ILTV, was required for clinical ILT to be manifested. 相似文献
Three known Cinchona alkaloids of the quinine type, quinine (1), cupreine (2), cinchonine (3), and the possible artifact cinchonine-HCl (3-HCl), along with two new ones, acetylcupreine (4) and N-ethylquinine (5), have been isolated from the bark of Remijia peruviana (Rubiaceae). Their stereochemical structures were established by high resolution NMR spectroscopy. Alkaloids 2-4 had antifeedant effects on Leptinotarsa decemlineata with varying potencies. Compound 4 was cytotoxic to both insect Sf9 and mammalian CHO cells after 48 h of incubation, while 3-HCl had stronger and selective cytotoxicity to Sf9. Quinine 1 had a moderate to low effect on Trypanosoma cruzi. Tumoral cells were also affected by these alkaloids, with 4 and 3-HCl being the most cytotoxic to all the cell lines tested. Overall, the 8R, 9S configurations, as in 3 and 3-HCl, as well as the C-6'acetylated alkaloid 4, with an 8S, 9R configuration, showed stronger biological effects. 相似文献