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61.
Bioremediation of cadmium contaminated soil using symbiosis between leguminous plant and recombinant rhizobia with the MTL4 and the PCS genes 总被引:3,自引:0,他引:3
Cadmium contamination in rice grains is one of the important issues in Asian countries. We have developed a novel bio-remediation system based on the symbiosis between leguminous plant and genetically engineered rhizobia. We designed two types of recombinant rhizobia, carrying two genes, synthetic tetrameric metallothionein (MTL4) and cDNA encoding phytochelatin synthase from Arabidopsis thaliana (AtPCS). The MTL4 and AtPCS genes were transferred to Mesorhizobium huakuii subsp. rengei B3, which can infect and form nodules on Chinese milk vetch, Astragalus sinicus. The two genes were fused to the nolB or nifH promoter, which generated nodule specific expression of these genes in strain B3. The two recombinant strains, B3(pMPnolBMTL4nifHPCS) and B3::nifHMTL4(pMPnifHPCS), showed 25 and 12-fold increase in Cd concentration, in the free-living cells, respectively. When these recombinant strains established the symbiotic relationship with A. sinicus, the symbionts increased Cd accumulation in nodules by two-fold in hydroponic culture. The expression of the both MTL4 and AtPCS genes showed additive effect on cadmium accumulation in nodules. We also applied these recombinant bacteria to rice paddy soil polluted with Cd (1mgkg(-1) dry weight soil). The accumulation of Cd increased not only in nodules but also in the roots of A. sinicus infected by the recombinant rhizobia. The accumulation of Cd in the plant roots infected by B3(pMPnolBMTL4nifHPCS) achieved three-fold than that by the wild-type B3. After two months of cultivation of the symbiont, a maximum of 9% of Cd in paddy soil was removed. Thus, the symbiosis will be useful in phytoremediation for heavy metals. 相似文献
62.
In February 2011, at the peak of an influenza outbreak, we performed a comprehensive analysis of the mass balances of four anti-influenza drugs—oseltamivir (OS), oseltamivir carboxylate (OC), amantadine (AMN), and zanamivir (ZAN)—in the urban area of the Yodo River system. This area includes three main river catchments (the Katsura, Uji, and Kidzu Rivers) and is home to 12 million people, about 10% of Japan’s population. Water was sampled at six main rivers and 13 tributary sites and eight sewage treatment plants (STPs). We concluded that the STP effluents were the major sources of the anti-influenza drug load in the Yodo River system (68–94% of total mass fluxes). Extended measurement throughout the Yodo River system further showed only small fluctuations of the ratio of OS to OC from 0.2 to 0.3, suggesting that OS and its metabolite are environmentally stable. The results also clearly showed the importance of reducing the levels of anti-influenza drugs in the water environment by reducing their emission at STPs. 相似文献
63.
64.
Cristina P. B. Melo Maria V. E. Grossmann Fábio Yamashita Elza Y. Youssef Luiz Henrique Dall’Antônia Suzana Mali 《Journal of Polymers and the Environment》2011,19(3):739-749
The objective of this work was to manufacture biodegradable films by two different processes (casting and extrusion), from
different combinations of cassava starch and xanthan gum. These films were produced by casting and by extrusion from six different
starch-xanthan gum combinations (0, 2, 4, 6, 8 and 10% w/w), containing glycerol as plasticizer (20% w/w) and were also characterized
according to their microstructure, optical, mechanical, and barrier properties. Scanning electron microscopy of the starch-xanthan
gum extruded films showed reticulated surface and smooth interior, suggesting that xanthan was driven to the surface and gelatinized
starch to the interior of the films during extrusion. Films manufactured by casting were entirely homogeneous. In general,
casted films presented lower opacity and water vapor permeability and higher stress at break than films manufactured by extrusion.
Xanthan gum addition affected mechanical properties of starch films, improving their stress and strain at break, especially
for extruded samples, but these properties did not show stability at different RH conditions. 相似文献
65.
Shigetaka Seki Yoichi Yamashita Hiroshi Kamikawaji Alfons Buekens Toshiaki Yoshioka 《Journal of Material Cycles and Waste Management》2018,20(4):2068-2076
It is of huge importance for sustainability to find a pragmatic solution for recycling of a variety of wastes emitted in small mass such as the case of wallpaper replacements. A combination of two-step sorting scheme and transportation of the wastes in collaboration with the wholesalers was proposed to enhance the efficiency of recycling. The two-step sorting consists of the first sorting at the wallpaper hanging sites to separate and group wastes in a way to avoid heavy additional burden on the hanging job. Secondary sorting is conducted at a Sorting Center to re-group wastes to send to an intermediate processing company for recycling. To minimize the costs for transportation, the grouped wastes emitted at the hanging sites are brought back by the hangers and kept temporally and then moved to the wholesaler(s) on the way to receive new materials. When the wastes at the wholesaler(s) become sufficiently large for economic transportation, a truck is arranged to collect the wastes to transport them to the Sorting Center. A feasibility study to test the practicality of the method confirmed that it could be operable and the cost would be comparable or lower than that currently incurred for disposal of the wastes. 相似文献
66.
The concentrations of PCDD/F and Co-PCB congeners in seawater, sediment, Pacific oyster, Japanese anchovy, marbled sole, and Japanese flounder samples from Sendai Bay, Japan, were analyzed. The compositions of total PCDD/F and total Co-PCB concentrations in sediment and Pacific oyster reflected that in seawater--the compositions of total PCDD, PCDF, and Co-PCB concentrations were approximately 60, 10, and 30%, respectively. The compositions in Japanese anchovy, marbled sole, and Japanese flounder were different from those in seawater and sediment-the ratio of total Co-PCB concentration to total PCDD/F plus Co-PCB concentrations in Japanese anchovy, marbled sole, and Japanese flounder was above 90%. Tetrachlorinated PCDDs (T4CDDs), such as 1,3,6,8- and 1,3,7,9-T4CDD, were the predominant congeners in seawater and sediment; the total T4CDD concentrations in seawater and sediment were approximately 46 and 48% of the total PCDD concentration. Furthermore, shipments of the herbicide 1,3,5-trichloro-2-(4-nitrophenoxy)benzene to Miyagi Prefecture, the so-called granary of Japan, were the highest in Japan over the last 12 years. The major sources of PCDD/Fs and Co-PCBs in Sendai Bay, which is in Miyagi Prefecture, are impurities in chlorinated herbicides. The order of concentration of PCDD/Fs was Pacific oyster > Japanese anchovy = marbled sole > Japanese flounder; the concentration in Japanese flounder, which is a higher-trophic-level consumer in the marine food web, was lower than that in shellfish (Pacific oyster) and Japanese anchovy, which are lower-trophic-level consumers. The order of concentration of Co-PCBs was Pacific oyster < Japanese anchovy = marbled sole < Japanese flounder; the concentrations in the higher-trophic-level consumers were higher than the concentrations in the lower-trophic-level consumers. Different PCDD/F congeners tended to bioaccumulate in different organisms. On the other hand, all species of Co-PCB congener tended to bioaccumulate in all organisms. 相似文献
67.
Leticia Burone Silvia Helena de Mello e Sousa Michel Michaelovitch de Mahiques Paulo Valente Aurea Ciotti Cíntia Yamashita 《Marine Biology》2011,158(1):159-179
Foraminiferal data were obtained from 66 samples of box cores on the southeastern Brazilian upper margin (between 23.8°–25.9°S
and 42.8°–46.13°W) to evaluate the benthic foraminiferal fauna distribution and its relation to some selected abiotic parameters.
We focused on areas with different primary production regimes on the southern Brazilian margin, which is generally considered
as an oligotrophic region. The total density (D), richness (R), mean diversity ([`(H¢ )] \overline{{H^{\prime } }} ), average living depth (ALD
X
) and percentages of specimens of different microhabitats (epifauna, shallow infauna, intermediate infauna and deep infauna)
were analyzed. The dominant species identified were Uvigerina spp., Globocassidulina subglobosa, Bulimina marginata, Adercotryma wrighti, Islandiella norcrossi, Rhizammina spp. and Brizalina sp.. We also established a set of mathematical functions for analyzing the vertical foraminiferal distribution patterns, providing
a quantitative tool that allows correlating the microfaunal density distributions with abiotic factors. In general, the cores
that fit with pure exponential decaying functions were related to the oligotrophic conditions prevalent on the Brazilian margin
and to the flow of the Brazilian Current (BC). Different foraminiferal responses were identified in cores located in higher
productivity zones, such as the northern and the southern region of the study area, where high percentages of infauna were
encountered in these cores, and the functions used to fit these profiles differ appreciably from a pure exponential function,
as a response of the significant living fauna in deeper layers of the sediment. One of the main factors supporting the different
foraminiferal assemblage responses may be related to the differences in primary productivity of the water column and, consequently,
in the estimated carbon flux to the sea floor. Nevertheless, also bottom water velocities, substrate type and water depth
need to be considered. 相似文献