不同碳源条件下草菇内切型纤维素酶基因（eg1）转录表达的分析

利用Northernblot方法分析了不同碳源条件下草菇切型纤维素酶基因(eg1)的表达.结果发现,在含有纤维素的液体培养基中生长10d,eg1在草菇菌丝中有高效表达;纤维二糖、α-乳糖、β-乳糖,也能诱导eg1的表达,但和纤维素相比,eg1的表达量相对较低,并且它们的诱导效应在加入这类糖12h后迅速减弱;槐糖和龙胆二糖的诱导作用非常弱.在天然稻草为基质的固体栽培料生长时,草菇eg1的表达和草菇菌丝生长与出菇相对应,在菌丝生长期(d8)可见eg1的表达,d12时菌丝已长满,表达减弱,在出菇及菇体的分化及增大期,eg1的表达量逐渐增强,在成熟期达到最高水平;表明在草菇菇体发育中需要更多碳源及能源的补充,eg1在这方面起着非常重要的作用.图4参14     

Indoor and outdoor air PBDE levels in a Southwestern US city

Levels of polybrominated diphenyl ether (PBDE) flame retardants have been increasing in humans and the environment for the past few decades. Human levels are markedly higher in the US than Europe. Although food appears to be a significant route of intake, food PBDE levels are not substantially higher in the US than Europe. House and office dust appear to be major routes of exposure with air believed to usually provide a lesser route of intake. Because there are very few measurements of airborne PBDE that have been performed in relevant microenvironments in the US, increased efforts to assess airborne PBDE in the US as sources of exposure are needed. This study reports, for the first time from a Southwestern US city in Texas, the results of measurements of airborne PBDE in multiple locations, two outdoor and six indoor (residential and office) from active air sampling with collection of a combination of both vapor- and particulate-phase PBDE. Higher PBDE levels were measured in indoor than outdoor air, which confirms previous findings. Of 11 measured congeners including BDE 209, total PBDE levels in two outdoor air samples were 112 and 125 pg m^?3 and the indoor air levels ranged from 175 to 1232 pg m^?3 with a median of 572 pg m^?3. These findings suggest that sources of air contamination with PBDE may be similar in Texas as elsewhere in North America. However, more sampling is required to (1) better determine if this is the case and (2) attempt to characterize potential sources of PBDE contamination in both indoor and outdoor air by analysis of congener patterns.     

Limitations in the use of potassium dichromate as a blood preservative for the analysis of organohalogenated compounds: two month results

For analysis of organochlorine contaminants in human tissue, the "gold standard" for preservation, storage, and shipping is usually freezing. However, this method can be difficult, if samples are taken in remote areas, and costly, when the samples must be shipped on dry ice. Therefore, a more simple and cost effective method of preservation is essential for remote field work. Potassium dichromate (K(2)Cr(2)O(7)) has been successfully employed in the preservation of human and cows' milk as well as chicken eggs. Our previous studies described the use of potassium dichromate for preservation of whole blood for analysis of dioxins, dibenzofurans, and PCBs. Potassium dichromate was found to successfully preserve blood at room temperature for 34 d with no significant differences in the measured concentrations of chemical contaminants or blood lipid level when compared to frozen samples. However, in a follow-up study, 3 months and 6 months of potassium dichromate preservation proved inadequate to preserve the samples for organic pollutant analysis. We noted that the lipid portion of the blood in the chemically preserved samples was declining in level or degrading, while the persistent organic pollutants remained intact at the same levels on a whole weight basis. To narrow down the window of efficacy for the use of potassium dichromate to preserve blood samples for analysis, the present study compared chemical preservation to freezing for an intermediate time period, 2 months. Similar to our previous findings at 3 and 6 months, at 2 months significant lipid degradation was observed in the chemically preserved samples. Chemically preserved samples had significantly higher levels of organochlorine contaminants (dioxins, dibenzofurans, and PCBs) when measured on a blood lipid basis but not on a wet weight basis compared to frozen samples. While 2 months of potassium dichromate preservation was not useful for obtaining accurate measure of dioxins, furans, and PCBs on a lipid basis, previous studies found this method of preservation to be useful for at least one month (Schecter, A., Pavuk, M., P?pke, O., Malisch, R., 2004. The use of potassium dichromate and ethyl alcohol as blood preservatives for analysis of organochlorine contaminants. Chemosphere 57, 1-7). However blood stored at -70 degrees C and at 22 degrees C with potassium dichromate gave similar results when expressed on a wet weight basis.     

不同碳源条件下草菇内切型纤维素酶基因(egl)转录表达的分析

利用Northern blot方法分析了不同碳源条件下草菇內切型纤维素酶基因(eg1)的表达.结果发现,在含有纤维素的液体培养基中生长10 d,eg1在草菇菌丝中有高效表达;纤维二糖、α-乳糖、β-乳糖,也能诱导eg1的表达,但和纤维素相比,eg1的表达量相对较低,并且它们的诱导效应在加入这类糖12 h后迅速减弱;槐糖和龙胆二糖的诱导作用非常弱.在天然稻草为基质的固体栽培料生长时,草菇eg1的表达和草菇菌丝生长与出菇相对应,在菌丝生长期(d 8)可见eg1的表达,d 12时菌丝已长满,表达减弱,在出菇及菇体的分化及增大期,eg1的表达量逐渐增强,在成熟期达到最高水平;表明在草菇菇体发育中需要更多碳源及能源的补充,eg1在这方面起着非常重要的作用. 图4 参14