Spontaneous revertants in modified S. typhimurium mutagenicity tests employing elevated numbers of the tester strain

Mutagenicity of indoor air containing environmental tobacco smoke: evaluation of a portable PM-10 impactor sampler

“…Mutagenicity Testing. Mutagenicity testing of each of the extracts was conducted with S. typhimurium strain TA98 using a modification (28) of the microsuspension procedure of Kado et al (19). Fifty microliters or more of dimethyl sulfoxide (DMSO) was added to the extracts and the mixtures were sonicated for 5 min at 35 °C to bring the material into solution.…”

“…Maximum slopes from the initial linear dose-response regions of each set of data were determined by using the Ames Fit program (29). Duplicates of all zero-dose plates were run and the spontaneous revertants were determined by subtracting the numbers of preexisting revertants (28). S9 prepared from Arochlorpretreated male Sprauge-Dawley rats was purchased from Litton Bionetic Inc. and had a stated protein content of 29 mg/mL.…”

Nanoengineered Bifidobacterium bifidum with Optical Activity for Photothermal Cancer Immunotheranostics

“…1−8 Additionally, the possibility of the development of potentially virulent revertants owing to genetic manipulation remains a concern. 9 Nanotechnological approaches are promising for improving the performance and synergistic effects of bacterial therapy. 9−12 In particular, nanotechnological approach-dependent photothermal conversion can significantly enhance the potential of bacterial cancer therapy.…”

“…The engineering of living bacteria has ushered in a new era of therapeutic applications in cancerous diseases. − In fact, several clinical trials on engineered bacterial therapy for cancer using anaerobic bacteria are currently underway because these bacteria exhibit specific tumor-targeting effects under hypoxic conditions and high controllability of cytotoxicity induction . However, complicated genetic engineering techniques are applied to bacterial therapeutics to attenuate bacterial toxicity and improve anticancer efficacy because these conventional methods often use naturally pathogenic bacteria with low medicinal value such as Salmonella typhimurium , Clostridium novyi , and Listeria monocytogenes . − Additionally, the possibility of the development of potentially virulent revertants owing to genetic manipulation remains a concern …”

“…Nanotechnological approaches are promising for improving the performance and synergistic effects of bacterial therapy. − In particular, nanotechnological approach-dependent photothermal conversion can significantly enhance the potential of bacterial cancer therapy. − For instance, Chen et al reported the chemical cross-linking of the external surface of the bacterial membrane of S. typhimurium with indocyanine green (ICG)-loaded nanoparticles as a photothermal agent for cancer hyperthermia . However, conventional nanotechnological approaches continue to use genetic manipulation for attenuating toxicity and improving the efficacy of bacteria.…”