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151.
自安徽、山东、湖北、江苏等地多点采集棉花红腐病、水稻恶苗病、玉米穗腐病的病组织,经分离、鉴定和纯化,获得107个串珠镰孢(Fusarium monilifoFine)菌株。对上述来源于棉花、水稻、玉米的串珠镰孢的菌落形态、生长速率和产孢量等生物学性状及其在无性后代的遗传与变异进行了研究。结果表明,不同寄主来源的串珠镰孢菌株的菌丝生长温度范围和最适温度大致相同,但在菌落形态特别是色素方面存在明显差异,生长速率和产孢量也存在显著差异。棉花菌株的平均生长速率最大,玉米菌株生长速率最小,水稻菌株生长速率居中,相同群体的不同菌株间生长速率有极显著差异;玉米菌株产孢量最大,棉花菌株产孢量最小,水稻菌株产孢量居中。方差分析显示,不同寄主菌株群体间产孢量存在显著差异,而同一寄主群体的不同菌株间产孢量均无显著差异,说明菌株产孢量大小主要与其寄主种类有关,而与地区来源关系不大。遗传测定结果表明,分离自棉花、玉米和水稻的串珠镰孢的菌落形态和生长速率在单分生孢子后代均可稳定遗传;产孢量性状遗传有两种情况:分离自棉花和水稻的串珠镰孢菌株Fm1和Fm31的产孢量性状在单分生孢子后代均可稳定遗传,而分离白玉米的串珠镰孢菌株Fm19的产孢量性状在单分生孢子第一代(CG1)发生变异。 相似文献
152.
Yuan-Fu Deng Shi-Di Tang Liang-Qiang Lao Shu-Zhong Zhan 《Inorganica chimica acta》2010,363(4):827-7300
Pure nanocrystallite magnesium titanate (MgTiO3) was conveniently synthesized by thermal decomposition of a cheap and water-soluble heterobimetallic single source precursor [Mg(H2O)5]2[Ti2(O2)2O(NC6H6O6)2]·7H2O at low temperature. This single source precursor was obtained in high yield and in a crystalline form from the quaternary system of MgO-Ti(OC4H9)4-H2O2-H3nta (H3nta = nitrilotriacetic acid) at pH 4.0. It was characterized by elemental analysis, IR spectrum, NMR, thermal gravimetric analysis and X-ray single-crystal diffraction. The morphology, microstructure, and crystallinity of the resulting MgTiO3 materials have been characterized by transmission electron microscopy and X-ray diffraction. The TEM image of the resulting MgTiO3 powders only consists of the nano-scale crystallites with the crystalline size of 30-100 nm. 相似文献
153.
Arpad Horvath 《The International Journal of Life Cycle Assessment》2006,11(4):229-239
Goal, Scope and Background This study provides a life cycle inventory of air emissions (CO2, NOx, PM10, and CO) associated with the transportation of
goods by road, rail, and air in the U.S. It includes the manufacturing, use, maintenance, and end-of-life of vehicles, the
construction, operation, maintenance, and end-of-life of transportation infrastructure, as well as oil exploration, fuel refining,
and fuel distribution.
Methods The comparison is performed using hybrid life cycle assessment (LCA), a combination of process-based LCA and economic input-output
analysis-based LCA (EIO-LCA). All these components are added by means of a common functional unit of grams of air pollutant
per ton-mile of freight activity.
Results and Discussion Results show that the vehicle use phase is responsible for approximately 70% of total emissions of CO2 for all three modes.
This confirms that tailpipe emissions underestimate total emissions of freight transportation as infrastructure, pre-combustion,
as well as vehicle manufacturing and end-of-life account for a sizeable share of total emissions. Differences between tailpipe
emissions and total system wide emissions can range from only 4% for road transportation's CO emissions to an almost ten-fold
difference for air transportation's PM10 emissions.
Conclusion Rail freight has the lowest associated air emissions, followed by road and air transportation. Depending on the pollutant,
rail is 50-94% less polluting than road. Air transportation is rated the least efficient in terms of air emissions, partly
due to the fact that it carries low weight cargo. It emits 35 times more CO2 than rail and 18 times more than road transportation
on a ton-mile basis. It is important to consider infrastructure, vehicle manufacturing, and pre-combustion processes, whose
life-cycle share is likely to increase as new tailpipe emission standards are enforced.
Recommendation and Outlook Emission factors, fuel efficiency, and equipment utilization contribute the most to uncertainty in the results. Further studies
are necessary to address all variables that influence these parameters, such as road grade, vehicle speed, and vehicle weight.
A focus on regional variation, end-of-life processes, fuel refining processes, terminals, as well as more accurate infrastructure
allocation between freight and passenger transportation would strengthen the model. 相似文献
154.
Wieland B Wittwer M Regula G Wassenaar TM Burnens AP Keller J Stärk KD 《Journal of applied microbiology》2006,100(2):316-324
AIMS: To develop a method for assessing the relative epidemiological significance of possible infection sources for human campylobacteriosis. METHODS AND RESULTS: Using fluorescent amplified fragment length polymorphism (AFLP), 243 apparently epidemiologically unrelated Campylobacter jejuni isolates were genotyped (77 human, 46 cattle, 49 pet and 71 poultry isolates). In total 136 different phena were identified, of which 48 were clusters grouping at least two isolates. Isolates from different sources were frequently clustered together, underlining the high degree of source mixing and the lack of host specificity of C. jejuni. The phena were classified into different phenon types according to the sources of the isolates they contained. The occurrence of these phenon types was analysed using an area-proportional Euler diagram to describe epidemiological relatedness among C. jejuni isolates. Group separation statistics revealed that 43% of analysed human isolates expressed maximum similarity to other human isolates, 9% to cattle isolates, 21% to pet isolates and 27% to poultry isolates; these results were in accordance with the pattern observed in the phenon cluster analysis. CONCLUSIONS: Based on the grouping of strains into molecular similarity clusters, ecological patterns between sources can be investigated. Significance and IMPACT OF THE STUDY: This approach is a new methodological contribution to establish the relative epidemiological significance of concurrent infection sources. 相似文献
155.
Papa R Glagla S Danchin A Schweder T Marino G Duilio A 《Extremophiles : life under extreme conditions》2006,10(6):483-491
The capability of microorganisms to utilize different carbohydrates as energy source reflects the availability of these substrates in their habitat. Investigation of the proteins involved in carbohydrate usage, in parallel with analysis of their expression, is then likely to provide information on the interaction between microorganisms and their ecosystem. We analysed the growth behaviour of the marine Antarctic bacterium Pseudoalteromonas haloplanktis TAC125 in the presence and in the absence of different carbon source. A marked increase in the optical density was detected when l-malate was added to the growth medium. Bacterial proteins differently expressed in the presence of l-malate were identified by proteomic profiling experiments. On the basis of their relative increase, six proteins were selected for further analyses. Among these, the expression of a putative outer membrane porin was demonstrated to be heavily induced by l-malate. The presence of a functionally active two-component regulatory system very likely controlled by l-malate was found in the upstream region of the porin gene. A non functional genomic porin mutant was then constructed showing a direct involvement of the protein in the uptake of l-malate. To the best of our knowledge, the occurrence of such a regulatory system has never been reported in Pseudoalteromonads so far and might constitute a key step in the development of an effective inducible cold expression system. 相似文献
156.
Rodríguez Couto S Rodríguez A Paterson RR Lima N Teixeira JA 《Letters in applied microbiology》2006,42(6):612-616
AIM: To produce high laccase activities from the white-rot fungus Trametes hirsuta in an in-house air-lift bioreactor (ALB). METHODS AND RESULTS: Trametes hirsuta was grown in a 6-l ALB. A fed-batch strategy with glycerol as an addition resulted in maximum laccase activity of 19,400 U l(-1), which was the highest reported from the fungus. CONCLUSION: The ALB configuration with additional glycerol resulted in high laccase activities. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provides useful information on how to produce high concentrations of laccase. 相似文献
157.
Vladimir Elisashvili Michel Penninckx Eva Kachlishvili Mikheil Asatiani Giorgi Kvesitadze 《Enzyme and microbial technology》2006,38(7):457-1004
It has been shown that the wood-rotting mushroom Pleurotus dryinus IBB 903 is able to effectively produce cellulases, xylanase, laccase, and manganese peroxidase in submerged fermentation of mandarin peels and tree leaves. Gradual increasing of lignocellulosic substrates concentration from 1 to 4–6% enhanced enzyme accumulation in culture liquid. A simple and inexpensive medium containing mandarin peels and yeast extract as sole carbon and nitrogen sources allowed simultaneous production of high levels of both hydrolases and oxidases by P. dryinus IBB 903. Supplementation of this medium by copper and manganese caused earlier and faster accumulation of laccase and manganese peroxidase increasing their yield by 1.5 and 7.5 times, respectively. In addition, by adding manganese to the medium it is possible to regulate the ratio of laccase and MnP in enzyme preparation. The presence of lignocellulosic substrate is the requisite for MnP production by P. dryinus IBB 903 since there was no production of MnP when mushroom has been cultivated in the synthetic medium with different carbon source. Among carbon source tested only utilization of glucose resulted to 21-fold increase of fungus laccase specific activity compared to control medium without carbon source. Carboxymethyl cellulase and xylanase appeared to be inducible enzymes. 相似文献
158.
Koo NY Li J Hwang SM Choi SY Lee SJ Oh SB Kim JS Lee JH Park K 《Biochemical and biophysical research communications》2006,342(4):1114-1122
We recently found that the concentration of HCO3- in guinea-pig saliva is very similar to that of human saliva; however, the entity that regulates HCO3- transport has not yet been fully characterized. In order to investigate the mechanism of HCO3- transport, we identified, cloned, and characterized a sodium bicarbonate (Na(+)/HCO3- cotransporter found in guinea-pig parotid glands (gpNBC1). The gpNBC1 gene encodes a 1079-amino acid protein that has 95% and 96% homology with human and mouse parotid NBC1, respectively. Oocytes expressing gpNBC1 were exposed to HCO3- or Na(+)-free solutions, which resulted in a marked change in membrane potentials (V(m)), suggesting that gpNBC1 is electrogenic. Likewise, a gpNBC1-mediated pH recovery was observed in gpNBC1 transfected human hepatoma cells; however, in the presence of 4, 4-diisothiocyanostilbene-2,2-disulfonic acid, a specific NBC1 inhibitor, such changes in V(m) and pH(i) were not observed. Together, the data show that the cloned guinea-pig gene is a functional, as well as sequence homologue of human NBC1. 相似文献
159.
The colony-forming ability of Escherichia coli genetically engineered to produce eicosapentaenoic acid (EPA) grown in 3mM hydrogen peroxide (H(2)O(2)) was similar to that of untreated cells. It was rapidly lost in the absence of EPA. H(2)O(2)-induced protein carbonylation was enhanced in cells lacking EPA. The fatty acid composition of the transformants was unaffected by H(2)O(2) treatment, but the amount of fatty acids decreased in cultures of cells lacking EPA and increased in cultures of cells producing EPA, suggesting that cellular EPA is stable in the presence of H(2)O(2) in vivo and may protect cells directly against oxidative damage. We discuss the possible role of EPA in partially blocking the penetration of H(2)O(2) into cells through membranes containing EPA. 相似文献
160.
Treponema denticola, frequently isolated from the human oral cavity, is thought to be a major pathogen of human periodontal disease. Recent developments in molecular analysis have clarified the surface structure of this microorganism and the characteristics of its pathogenic factors. Structural analysis of the outer sheath showed T. denticola to have a new type of outer membrane lipid. Limited exposure of the major outer sheath protein is suggested by electron-microscopic analysis. A protease-deficient mutant has revealed the roles of the protease in the organization of the outer sheath material and in T. denticola pathogenicity. The surface features that contribute to the pathogenicity of T. denticola in periodontal disease are gradually being elucidated, and are reviewed. 相似文献