Microelectrode determination of oxygen profiles in microbial slime systems
Microelectrode determination of oxygen profiles in microbial slime systems
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DOI：
10.1021/es60035a004
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发表时间：
1969-12
影响因子：
11.4
通讯作者：
W. Whalen;H. Bungay;W. M. Sanders
中科院分区：
文献类型：
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作者：
W. Whalen;H. Bungay;W. M. Sanders
Whalen 等人 (1967) 描述的微电极属于极谱型，由一根拉长、直径为 1.5 µ 的锥形点的玻璃毛细管组成。管内填充金属合金，距尖端 10-20 µ 以内。在合金上电镀一层金，凹槽的其余部分用火棉胶填充。涂有氯化银的纯银线用作单独的阳极。在电极上施加 0.6-1.1 的电压，并用皮安计-伺服记录仪组合记录电流的变化。电极之间的电流与氧活度呈线性关系，并且对搅拌相对不敏感。粘液膜是在小型连续培养生长室中形成的，细菌生长在专门准备的显微镜载玻片上。为了在探测细胞下层或附着层附近时保护脆弱的阴极尖端，在有机玻璃载玻片上预先钻好的孔中填充了 2% Difco 琼脂。生长室中接种了异养细菌，包括从污染溪流中获得的至少 18 种细菌（Sanders，1966），并密封 24 小时。在此附着期结束时，流量为 280 毫升。启动每分钟 20 ppm 的营养肉汤 (BBL) 并维持八天。沿载玻片的基质速度为每秒1.5英尺，温度为27℃。然后移除室的顶部，并将含有粘液的底部夹在Leitz Panphot显微镜的载物台上。该室连接到入口深度（微米）。 图 1. 使用微电极确定的连续流动系统中细菌粘液的溶解氧分布。营养液流速为每秒 1.5 英尺，温度为 27°C。含有营养肉汤 20 毫克。每升 (O—O)，75 µ 深度以下粘液中的氧气稳定在百万分之 5.5。含 500 毫克。每升营养肉汤 (·—·)。轮廓达到 150 µ，然后稳定在百万分之 0.25
The microelectrode described by Whalen et al.(1967) was of the polarographic type and consisted of a glass capillary tube drawn out to a long, tapering point 1.5 µ in diameter. The tube was filled, to within 10-20 µ of the tip, with a metal alloy. A layer of gold was electroplated on the alloy, and the remainder of the recess was filled with collodion. A pure silver wire coated with silver chloride served as a separate anode. A voltage of 0.6-1.1 was impressed across the electrodes, and changes in current were recorded with a picoammeter-servo recorder combination. Current flow between the electrodes is linear with the oxygen activity, and is relatively insensitive to stirring. The slime film was developed in a small, continuousculture growth chamber, with the bacteria growing attached on an especially prepared microscope slide. To protect the delicate cathode tip when probing near the lower or attaching layer of cells, predrilled holes in the Plexiglassslide were filled with 2% Difco agar. The growth chamber was seeded with heterotrophic bacteria, including at least 18 species obtained from a polluted stream (Sanders, 1966), and sealed for 24 hours. At the end of this attachment period, a flow of 280 ml. per minute of 20 parts per million nutrient broth (BBL) was initiated and maintained for eight days. The substrate velocity along the slide was 1.5 feet per second and the temperature was 27 C. Then the top of the chamber was removed and the bottom containing the slime was clamped onto the stage of a Leitz Panphot microscope. The chamber was connected to an inletDEPTH (MICRONS) Figure 1. Dissolved oxygen profiles for bacterial slimein a con-tinuous-flow system determined with microelectrode. Nutrient flow was 1.5 feet per second andtemperature 27 C. With nutrient broth 20 mg. per liter (O—O), the oxygen in the slime stabilized at 5.5 parts per million below 75 µ in depth. With 500 mg. per liter nutrient broth (·—·). the profile reached 150 µ before stabilizing at 0.25 parts per million