Composting of the Undaria pinnatifida (wakame) seaweed was conducted after inoculation with 6×10(8) CFU g(-1)Halomonas sp. AW4 and the alginate-degrading bacterium Gracilibacillus sp. A7. Inoculation with strains A7 and AW4 resulted in 27.8% and 24.7% degradation of U. pinnatifida dry mass after 168 h, whereas only 17.5% degradation occurred in the uninoculated control. The C/N ratio decreased in the A7 and AW4 inoculated compost by 7.0% and 9.2% after 72 h, but increased by 11.5% in the control. Inoculation with A7 resulted in 2.8 times faster degradation of alginate and 1.2 and 1.6 times higher levels of reducing sugars and unsaturated sugars than inoculation with AW4. The compost produced from the inoculation with A7 had low plant toxicity as measured by germination experiment. The results suggest that inoculation of wakame with alginate-degrading bacteria not only shortened the length of composting but also created seaweed compost with good fertilizer qualities. 相似文献
The responses of wheat Triticum aestivum, rice Oryza sativa, earthworms Eisenia foetida, and prawns Penaeus japonicus to combined acetochlor-Cu, Cd-Zn were studied in hydroponic and soil-culturing systems using the methods of ecotoxicology.
In particular, systematically quantitative analyses were documented by field experiments. Results showed that ecotoxicological
effects under the combined pollution were not only related to chemical properties of pollutants but also dependent on the
concentration level of pollutants, in particular on the combination of concentrations of pollutants in ecosystems. Additionally,
species of organisms, especially the type of ecosystem, determined the influences. To some extent, biological tissue targets
attacked by pollutants were an important factor. 相似文献
Characteristics of cadmium (Cd) accumulation and tolerance in Rorippa globosa (Turcz.) Thell., a species with some characteristics of cadmium hyperaccumulation were further investigated and compared
with a closely related species, Rorippa islandica. The results showed that there was no phytotoxicity for R. globosa leaves or reduction in biomass when treated with 25 μg Cd g−1, although the concentration of Cd accumulated in the leaves was up to 218.9 μg Cd g−1 dry weight (DW). On the contrary, Cd toxicity was observed in R. islandica leaves by way of determining changes in fresh weight (FW), malondialdehyde (MDA) level and chlorophyll content while treated
with 25 μg Cd g−1 DW. R. globosa had stronger self-protection ability than R. islandica to adapt to oxidative stress caused by Cd. Application of Cd significantly increased the activity of superoxide dismutase
(SOD) in leaves, the activity of peroxidase (POD) in roots, and the activity of catalase (CAT) in leaves and roots of R. globosa. By contrast, in R. islandica, the activity of antioxidant enzymes was inhibited or unchanged by various Cd treatments. However, R. globosa leaves had higher activity of antioxidant enzymes such as SOD and POD than that of R. islandica. The antioxidative defense systems in R. globosa might play an important role in Cd tolerance. The Cd treatments significantly induced the synthesis of phytochelatins (PCs)
in the two species. Leaf PCs and Cd accumulation by R. globosa were much greater than those by R. islandica, but root PCs and Cd accumulation by R. islandica were much greater than those by R. globosa, suggesting that PCs in leaves may be a biomarker of Cd hyperaccumulation, and the synthesis of PCs may be related to an
increase in the uptake of Cd ions into the cytoplasm, not the primary mechanism for Cd tolerance. 相似文献
Soil samples were collected from 7 sites in the up-, mid-and down-reach along and nearby the wastewater irrigation channel, western Shenyang of China. The concentrations of selected pollutants (mineral oil, PAHs - polycycle aromatic hydrocarbons and Cd) were determined by UV spectrometer, HPLC and AAS (atomic adsorption spectrometer) spectrometer, respectively. Toxicity effects of soils were evaluated by seedling emergence test with root length of wheat as the end-point and by earthworms test with the mortality rate and inhibition rates of body weight as endpoints. Results showed accumulation of pollutants for most soils with concentration of 200.2 mg.kg−1∼1600 mg.kg−1 for mineral oil, 0.33 mg.kg−1∼1.81 mg.kg−1 for Cd and 900.16 mg.kg−1 ∼ 2737.91 mg.kg−1 for PAHs. The inhibition rates of root elongation were from −20% up to 40 %, and mortality rates of earthworms ranged from 0%∼40% from the exposure period of two weeks to eight weeks by sampling interval of two weeks, the inhibition rates of earthworm growth were from −19.36% to 34.53%, showing effects of stimulation at 2 weeks to an increasing effects of inhibition at 4, 6 and 8 weeks, respectively. Mortality rates correlated with the loss of body weight of earthworms.
This study indicated the potential risk of pollutants of environmental low content in soil by the determination of selected chemicals combined with toxicity indexes.
Two different molecular weights of chitosan were pulverized to nanopowders by ultrafine milling. The nanopowders were characterized by viscometry small angle X-ray scattering (SAXS), transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), FT-IR spectroscopy and UV-vis spectroscopy. Our results showed that ultrafine milling effectively reduced the particle size of chitosan to a nanoscale. The viscosity average molecular weight (Mv) of chitosan was decreased by the milling treatment. The crystalline structure of chitosan was destroyed by the milling since the nanopowder exhibited an amorphous XRD pattern. In addition, thermal stability of the low molecular weight chitosan was decreased after the milling treatment. FT-IR and UV-vis spectra showed that the milling process did not cause significant changes in the chemical structure of chitosan. 相似文献
From an aborted bovine fetus in China, a bacterial strain named NI was isolated and identified as Brucella melitensis by a PCR assay. Strain NI was further characterized as B. melitensis biovar 3 using biochemical assays. Here we report the complete genome sequence of strain NI. 相似文献
Allantoin is one of important nitrogenous compounds in manure. In this study, the simulation experiment of aerobic composting was adopted to explore concentration changes, degradation and relevant influencing factors of allantoin-N during six manure composting. The result showed that the allantoin-N concentration was markedly different among different manures. The various livestock and poultry excreted 1.92-11.14gkg(-1) allantoin-N which accounted for 9.98-32.27% of the total excreted nitrogen. The changing trend of the allantoin-N concentration firstly increased (for 0-14 days), then decreased (for 14-70 days) during different manure composting, and the allantoin-N concentration after composting was lower than the initial allantoin-N concentration in all manure composting. During allantoin degradation for 14-70 days of composting, the half-life of allantoin-N was 57.76 days in broiler manure, 46.21 days in layer-hen manure, 27.73 days in hog manure, 25.67 days in sow manure, 38.51 days in young pig manure and 15.75 days in dairy manure, and the sequence in the half-life was chicken manure>pig manure>dairy manure. Allantoin degradation conformed to first-order kinetics. Through the correlation analysis, hippuric acid, hydrolyzable nitrogen, amino acid-nitrogen, HUN fraction, NO(3)(-)-N and total hydrolyzable nitrogen could be closely related to allantoin-N transforming during composting. Humification could be the main influencing factor for reducing allantoin-N concentration during composting. 相似文献