Bedard D L, Unterman R, Bopp L H, Brennan M J, Haberl M L, Johnson C
Appl Environ Microbiol. 1986 Apr;51(4):761-8. doi: 10.1128/aem.51.4.761-768.1986.
We designed a rapid assay that assesses the polychlorinated biphenyl (PCB)-degradative competence and congener specificity of aerobic microorganisms, identifies strains capable of degrading highly chlorinated biphenyls, and distinguishes among those that degrade PCBs by alternative pathways. Prior attempts to assay PCB-degradative competence by measuring disappearance of Aroclors (commercial PCB mixtures) have frequently produced false-positive findings because of volatilization, adsorption, or absorption losses. Furthermore, these assays have generally left the chemical nature of the competence obscure because of incomplete gas chromatographic resolution and uncertain identification of Aroclor peaks. We avoided these problems by using defined mixtures of PCB congeners and by adopting incubation and extraction methods that prevent physical loss of PCBs. Our assay mixtures include PCB congeners ranging from dichloro- to hexachlorobiphenyls and representing various structural classes, e.g., congeners chlorinated on a single ring (2,3-dichlorobiphenyl), blocked at 2,3 sites (2,5,2'5'-tetrachlorobiphenyl), blocked at 3,4 sites (4,4'-dichlorobiphenyl), and lacking adjacent unchlorinated sites (2,4,5,2',4',5'-hexachlorobiphenyl). The PCB-degrative ability of microorganisms is assessed by packed-column gas chromatographic analysis of these defined congener mixtures following 24-h incubation with resting cells. When tested with 25 environmental isolates, this assay revealed a broad range of PCB-degradative competence, highlighted differences in congener specificity and in the extent of degradation of individual congeners, predicted degradative competence on commercial PCBs, and (iv) identified strains with superior PCB-degradative ability.
我们设计了一种快速检测方法，用于评估需氧微生物对多氯联苯（PCB）的降解能力和同系物特异性，识别能够降解高氯代联苯的菌株，并区分通过替代途径降解PCB的菌株。此前通过测量Aroclors（商业PCB混合物）的消失来检测PCB降解能力的尝试，由于挥发、吸附或吸收损失，经常产生假阳性结果。此外，由于气相色谱分辨率不完整以及Aroclor峰的鉴定不确定，这些检测通常使降解能力的化学性质模糊不清。我们通过使用定义明确的PCB同系物混合物，并采用防止PCB物理损失的孵育和提取方法，避免了这些问题。我们的检测混合物包括从二氯代到六氯代联苯的PCB同系物，代表各种结构类别，例如单环氯化的同系物（2,3 - 二氯联苯）、在2,3位受阻的（2,5,2',5'-四氯联苯）、在3,4位受阻的（4,4'-二氯联苯）以及缺乏相邻未氯化位点的（2,4,5,2',4',5'-六氯联苯）。在与静息细胞孵育24小时后，通过对这些定义明确的同系物混合物进行填充柱气相色谱分析，来评估微生物的PCB降解能力。当用25株环境分离株进行测试时，该检测方法揭示了广泛的PCB降解能力，突出了同系物特异性和单个同系物降解程度的差异，预测了对商业PCB的降解能力，并识别出具有卓越PCB降解能力的菌株。
