Effects of Alkylphosphates and Nitrous Oxide on Microbial Degradation of Polycyclic Aromatic Hydrocarbons

We conducted a series of liquid-culture experiments to begin to evaluate the abilities of gaseous sources of nitrogen and phosphorus to support biodegradation of polycyclic aromatic hydrocarbons (PAHs). Nutrients examined included nitrous oxide, as well as triethylphosphate (TEP) and tributylphosphate (TBP). Cultures were established using the indigenous microbial populations from one manufactured gas plant (MGP) site and one crude oil-contaminated drilling field site. Mineralization of phenanthrene was measured under alternative nutrient regimes and was compared to that seen with ammoniacal nitrogen and PO₄. Parallel cultures were used to assess removal of a suite of three- to five-ring PAHs. In summary, the abilities of the different communities to degrade PAH when supplemented with N₂O, TEP, and TBP were highly variable. For example, in the MGP soil, organic P sources, especially TBP, supported a considerably higher degree of removal of low-molecular-weight PAHs than did PO₄; however, loss of high-molecular-weight compounds was impaired under these conditions. The disappearance of most PAHs was significantly less in the oil field soil when organophosphates were used. These results indicate that the utility of gaseous nutrients for PAH bioremediation in situ may be limited and will very likely have to be assessed on a case-by-case basis.     

树实验种群的繁育

探讨了树实验种群的繁育。结果是5对成年树在7个月内共产11窝31只仔树。27只出生后即人工喂养的仔树中,25只健康存活至进入动物实验。成年树平均产仔周期为（52±8.9）d;仔树的人工喂养成活率为92.6%。可以认为树实验种群的人工繁育是可行的。人工繁育的树有望取代野外捕获的树用于有关的动物实验研究。     

Agrotis segetum雄蛾触角叶性信息素反应神经元对电刺激触角神经的反应

为探讨电刺激Agrotis segetum雄蛾触角神经是否可以作为MGC中神经元的识别手段,采用细胞内电生理记录方法,共记录34个对性信息素有反应的MGC神经元,并测试了其中12个神经元对性信息素刺激的反应,22个神经元对性信息素刺激和电刺激的反应。结果表明,MGC神经元对性信息素及电刺激的反应模式基本一致,为一种双相反应模式。两种刺激方式均能诱导出兴奋反应,电刺激得到的兴奋反应比由信息素刺激引起的要短;MGC神经元对两种刺激的超极化反应（抑制反应）幅度影响没有显著性差别,在电刺激实验的22个神经元上,超极化反应幅度和抑制时间都与神经元本身放电频率有一定的相关性。超极化反应是在LN参与下一定的神经回路对刺激所产生的反应而形成的。这提示两种刺激所作用的神经回路应是一致的,但从整个实验过程记录到的神经元情况来看,还须进一步结合形态学实验来验证电刺激触角神经作为MGC神经元的识别手段。     

Limited Roles for Salicylate and Phthalate in Bacterial PAH Bioremediation

We have isolated and identified 12 previously unreported strains of polycyclic aromatic hydrocarbon (PAH)-degrading bacteria. Three of these isolates belong to the genus Burkholderia, with the remainder comprised of two Pseudomonas species, and seven strains from the genus Sphingomonas. These isolates were examined for their ability to utilize a variety of three- to five-ring PAHs as sole sources of carbon and energy. All were also checked for the ability to grow on salicylic acid and phthalic acid, two compounds that are key intermediates in almost all published PAH degradative pathways. Only 3 of the 12 strains were able to grow on both of these monoaromatic acids, while three others (all Sphingomonas) could not grow on either. The implications of these findings on the universal applicability of known PAH catabolic pathways, and on possible induction of PAH degradation by pathway intermediates, are discussed.