毒性物質對Photobacterium phosphoreum於不同培養及測試條件下之抑制效應研究

Abstract

本研究針對螢光茵的不同的培養條件下，包括了連續式與批次式的培養狀況下，觀察其對毒性物質的敏感度變化情形。在連續式培養下，以兩種不同的稀釋率(0.5day-1及1.5day-1)培養，以兩種重金屬及十六種有機物比較具敏感性變化，發覺在1.5day-1的稀釋率下其敏感度較佳。在批次培養中以不同的培養條件，包括生長期的不同、培養基的差異、稀釋比例不同、生長的鹽度不同，及以超音波破壞細胞膜的方式，對重金屬Cu及三種有機物的敏感度做比較，由結果顯示螢光菌在穩定生長期時其敏感度較對數生長期時高，而培養基的稀釋比例較高時也會提高螢光菌的敏感度，這在三種不同的培養基下均得此種結果。對於在不同的鹽度生長下，螢光菌會有不同的生長及發光狀況，對毒性的敏感度而言以在鹽度為2%∼3%的生長條件下為佳，螢光菌經超音波的破壞之後，由於毒性物質對螢光的抑制更直接，故能有效的提高其敏感度。 將本研究與E.coli的攝氧率實驗結果比較具相關性不佳，而敏感度以螢光茵的敏感度高出甚多，相關性不佳的原因在於不同物種問的差異，包括了毒性的反應位址及量測終點。這在與Microtox的毒性試驗結果可得到驗證，將本研究之螢光菌結果與Microtox做比較，發現其有不錯的相關係數，這代表了在同物種間其毒性反應的一致性。 本研究對螢光菌在不同的生長條件下，對其敏感度做一相對的比較，而其與Microtox的毒性預測上提供了良好的相關性，且由於自行培養的條件下，對成本的降低及便利上也有較佳的方式。本研究發現了螢光菌的敏感度會受一些因素的影響，這對以後的螢光抑制反應提供了珍貴的資料。

Luminescence responses of Photobacterium phosphoreum to heavy metals and organic chemicals in various culture and test conditions is evaluated. There are two heavy metals and sixteen organic chemicals tested in continuous culture with two different dilution (0.5 day-1 and 1.5 day-1). It is apparent that the luminous bacterial cultured in dilution rate 1.5 day-1 is more sensitivity. The luminous bacterial is also cultured and tested in batch system with different conditions, such as different growth phase, different culture medium, different dilution, and different salinity. There are one heavy metal Cu and three organic chemicals tested and compared for these culture conditions. Results have been observed that sensitivity of the luminous bacterial is higher in steady state phase than in exponential phase. And its sensitivity is also higher with high dilution medium. The same results have been shown in three different culture medium. It is shown that the luminous bacterial cultured in 2%-3% salinity medium has superior Sensitivity and maximum luminescence. When the luminous bacterial is onicated we can observe that the EC50 values are lower. This is because that cell membrane is destroyed, and toxicants can react with bactenal more directly. P. phosphoreum has higher sensitivity than Escherichia coli, but luminescence inhibition test of the luminous bacterial compared with S.OUR(specific oxygen uptake rate) test of E.coli exhibit bad relationship coefficient. This is probably because that different species have different reaction locations and measurement endpoints. It is proved that the luminescence inhibition test exhibits good relativity with Microtox test. This study derives that sensitivity of the luminous bacterial can be influenced with different major factors, and show precious data about the luminescence inhibition toxicity test.