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1.
In this paper, the photosynthetic production of short-chain-length/medium-chain-length polyhydroxyalkanoate (PHA) copolymers is reported. The wild-type and highly active doubly mutated PHA synthase 1 (S325T/Q481K, abbreviated ST/QK) genes from Pseudomonas sp. 61-3 were introduced into Arabidopsis thaliana. Peroxisome targeting signal 1 (PTS1) was used to target PHA synthases into the peroxisome to synthesize PHA from the intermediates of the β-oxidation pathway. The transgenic Arabidopsis produced PHA copolymers consisting of 40–57 mol% 3-hydroxybutyrate, 21–49 mol% 3-hydroxyvalerate, 8–18 mol% 3-hydroxyhexanoate, and 2–8 mol% 3-hydroxyoctanoate. The maximum PHA contents were 220μ g/g cell dry weight (cdw) in leaves, and 36μ g/g cdw in stems, respectively. The expression of the ST/QK mutated PHA synthase in leaves gene did not lead to significant difference in PHA content and monomer composition of PHAs, compared to the wild-type PHA synthase gene, suggesting that the supply of monomers may be a rate-determining step of PHA biosynthesis in the peroxisome. However, in stems, there were significant differences dependent on whether the wild-type or ST/QK mutated PHA synthase was expressed. These results suggest that tissue-specific monomer availability is important in determining the final mol% composition of PHA copolymers produced by the peroxisome in plants.  相似文献   
2.
This paper describes the chemistry of porewater when constructing different soil layers on acidic weathered rock of a closed mine to remediate the surface environment. Three cases were set on a flat surface of the site, all under different layer systems. Case 1 was only composed of weathered rocks. A top neutralization layer was constructed on the weathered rocks in case 2, whereas both an upper low-permeable and middle neutralization layers were constructed on the weathered rocks in case 3. The low-permeable layer of 30?cm thick consists of clay, and the neutralization layer of 30?cm thick consists of the mixture of the weathered rock and calcium carbonate as a neutralizer. Porewater sampling systems and soil sensors to measure temperature, water content, and electrical conductivity were set at different depths. In case 1, steadily high concentrations of heavy metals were observed regardless of the depth, and the pH ranged from 2 to 4. In cases 2 and 3, a dramatic decrease in concentrations of heavy metals was observed, even below the neutralization layer. For both cases, pH values were circumneutral. There were no significant seasonable changes in heavy metals concentrations and pH of porewater by considering the temperature and precipitation. In addition, the water content of the layers in case 3 fluctuated more mildly than that in cases 1 and 2, indicating that the low-permeable layer reduced the rate of infiltration. Therefore, a significant reduction in the load of heavy metals released from the site can be achieved by both implementing neutralization and low-permeable layers.  相似文献   
3.
To learn more about the biodegradation of potassium bromate, the decomposition of bromate in various tissues of rats was studied. Bromate was degraded very slowly in human saliva and plasma of rat. However, nearly all tissue homogenates and red blood cells could degrade bromate by a mechanism which exhibited some stability to heat. Furthermore, it was suggested that the bromate degradation active component in the supernatant fraction of a liver homogenate was in part glutathione.  相似文献   
4.
This study investigated the production of d-lactic acid from unutilized sugarcane bagasse using steam explosion pretreatment. The optimal steam pressure for a steaming time of 5?min was determined. The steam-exploded sugarcane bagasse was hydrolyzed using cellulase (Meicelase) and then the hydrolyzate was subjected to fermentation substrate. By enzymatic saccharification using Meicelase, the highest recovery of glucose from raw bagasse, 73.7?%, was obtained at a steam pressure of 20?atm. For extracted residue with water after steam explosion, the glucose recovery increased up to 94.9?% at a steam pressure of 20?atm. These results showed that washing with water is effective in removing enzymatic reaction inhibitors. After steam pretreatment (steam pressure of 20?atm), d-lactic acid was produced by Lactobacillus delbrueckii NBRC 3534 from the enzymatic hydrolyzate of steam-exploded bagasse and washed residue. The conversion rate of d-lactic acid obtained from the glucose concentration was 66.6?% for the hydrolyzate of steam-exploded bagasse without washing with water and 90.0?% for that derived from the extracted residue with water after steam explosion. These results also demonstrated that the hydrolyzate of steam-exploded bagasse (without washing with water) contains fermentation inhibitors and washing with water can remove them.  相似文献   
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Buckwheat tea waste (BWTW) and barley tea waste (BTW), by-products of the beverage industry, are alternative carbohydrate sources for ethanol production. In this study, optimal enzyme loading for enzymatic saccharification of BWTW and BTW was determined, and simultaneous saccharification and fermentation (SSF) was performed by Saccharomyces cerevisiae and Mucor indicus to produce ethanol. Optimal enzyme loading for enzymatic saccharification of 2?% w/v BWTW and BTW was 0.5?% (weight of enzyme/weight of tea wastes) for BWTW and 0.1?% for BTW. Ethanol production from BWTW by S. cerevisiae and M. indicus after 48?h of SSF was 49.9/100?g of BWTW and 47.9/100?g of BWTW, respectively, with 0.5?% enzyme loading. Ethanol production from BTW by S. cerevisiae and M. indicus after 48?h of SSF was 20.5/100?g of BTW and 21.6/100?g of BTW, corresponding to 62 and 66?% of the theoretical yield based on starch content, respectively, with 0.1?% of enzyme loading. Furthermore, S. cerevisiae produced 76?% of the theoretical yield based on the total glucose from starch in BWTW and BTW when a mixture of BWTW and BTW was used as a substrate, with 0.2?% enzyme loading and no additional nitrogen or mineral sources.  相似文献   
7.
Potassium Bromate was administered orally to rats and its fate in the body was studied. The bromate was rapidly absorbed from the digestive tract and was partly excreted in the urine within two hours of administration. No bromate was detected in body organs or in the blood 24 hours after dosing. Excretion of bromate into the urine was proportional to the dose, except that at 2.5mg/kg or less no excretion was observed. The administration of bromate increased the bromide concentration in various organs and in urine.  相似文献   
8.
The Great East Japan Earthquake in March 2011 devastated the eastern region of Japan.Due to the resulting nuclear accident,Japanese Cabinet decided to revise its energy policies.The Energy and Environment Council in National Policy Unit published options on the nation’s scenarios for energy and economy in 2030.We estimated the economic impacts of the options to national economy and households in 2030.Finally,we clarified significant factors to establish a secure,affluent and low-carbon society based on the energy scenarios.  相似文献   
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10.
Concern over global declines among amphibians has resulted in increased interest in the effects of environmental contaminants on amphibian populations, and more recently, this has stimulated research on the potential adverse effects of environmental endocrine disrupters in amphibians. Laboratory studies of the effects of single chemicals on endocrine-relevant endpoints in amphibian, mainly anuran, models are valuable in characterizing sensitivity at the individual level and may yield useful bioassays for screening chemicals for endocrine toxicity (for example, thyroid disrupting activity). Nevertheless, in the UK and Japan as in many other countries, it has yet to be demonstrated unequivocally that the exposure of native amphibians to endocrine disrupting environmental contaminants results in adverse effects at the population level. Assessing the potential of such effects is likely to require an ecoepidemiological approach to investigate associations between predicted or actual exposure of amphibians to (endocrine disrupting) environmental contaminants and biologically meaningful responses at the population level. In turn, this demands recent but relatively long-term population trend data. We review two potential sources of such data for widespread UK anurans that could be used in such investigations: records for common frogs and common toads in several databases maintained by the Biological Records Centre (UK Government Centre for Ecology and Hydrology), and adult toad count data from 'Toads on Roads' schemes registered with the UK wildlife charity 'Froglife'. There were little abundance data in the BRC databases that could be used for this purpose, while count data from the Toads on Roads schemes is potentially confounded by the effects of local topology on the detection probabilities and operation of nonchemical anthropogenic stressors. For Japan, local and regional surveys of amphibians and national ecological censuses gathering amphibian data were reviewed to compile survey methodologies and these were compared with methods used in the UK and other countries. Substantial consensus exists in amphibian survey methodologies and this should be exploited in the initiation of coordinated monitoring programs for widespread and common anuran amphibians in Japan and the UK to generate long-term robust and standardized population trend data. Such data would support comparative ecoepidemiological assessments of the impact of environmental endocrine disrupters in these two cooperating countries.  相似文献   
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