Assays using microorganism

Because of the numerous benefits of Toxkit assays, they can be used for sample testing even by small analytical laboratories and local monitoring stations for routine toxicity assessments of environmental samples as well as in emergencies. The use of standard organisms means that assays can be standardized and that repeatable results can be obtained in different laboratories. Another, not unimportant aspect is that conducting toxicity assays on microorganisms does not require the consent of an ethical committee.77 Table 9.3 provides information on microbioassays commercially available in kit form (Toxkit).73... 

In the benzoquinone group, inhibition assays using Escherichia coli and Saccharomyces cerevisiae revealed the inhibitory effects of 1,4-benzoquinone and toluquinone against all tested microorganisms [189],... 

Figure 2. Agar-overlay assay used to screen for hydantoinase-producing microorganisms.

Evaluation of the brewery CIP system and its effectiveness is usually determined using off-line laboratory analysis or portable measuring devices. This typically involves dyes such as riboflavin or ATPase activity assays used to determine the presence of hving microorganisms. 

Fig. 13.4 Workflow for a phage-amplification assay using stable-isotope labeled phages to simultaneously determine the presence of Staphylococcus aureus in a sample, as well as the susceptibility of microorganism to two antibiotics—clindamycin and cefoxitin. (Reprinted with permission from Rees et al. (2015), copyright 2015, American Chemical Society)...

The first assays used Leuconostoc mesenteroides (ATCC 9135) and Tetrahymena pyriformis, but Lactobacillus casei (ATCC 7469) is the microorganism most commonly employed nowadays in these studies. 

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