Salmonella strains

The bacteria are exposed to a potential mutagen on a medium without histidine, and the number of bacterial colonies able to grow is scored. These colonies arise from a cell which has undergone a specific back mutation which results in the bacteria being proto trophic for histidine. Table II lists the Salmonella strains utilized in this phase of the work. 

ACS Symposium Series American Chemical Society Washington, DC, 1980. 

HIS BACTERIA USED IN REVERSION (AMES TEST) STUDIES 

The coordination compounds used in this work were synthesized 

Chromium Complexes. Table IV contains the results on chromium compounds. Like rhodium, a ais dihalo structure seems to confer mutagenic properties on the complex. Unlike the rhodium complexes, no activity is observed in the ois dihalopolyamine complexes. Several other complexes are active too, but these undergo sufficiently rapid ligand exchange that we are unsure as to the 

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Mellon AA, Hassani L (1999) Antibiotic resistance of Salmonella strains isolated from children living in the wastewater-spreading field of Marrakesh city (Morocco). World J Microbiol Biotechnol 15 81-85... 

Hanai, K. Satake, M. Nakanishi, H. Venkateswaran, K. Comparison of commercially available kits with standard methods for detection of Salmonella strains in foods. Appl. Environ. Microbiol. 1997, 63,775-778. 

In contrast to the results with BP, incubation of BP-7,8-dihydrodiol with ram seminal vesicle microsomes and arachidonate generates a species that is strongly mutagenic to Salmonella strains TA98 and TA100 (Figure 3) (22). Formation of the mutagen is inhibited by... 

The Use of the Plasmid pKMlOl. Salmonella typhimurium LT2 strains do not appear to possess classical error-prone repair as found in E. coli strains and some other members of the Enterobacteria (Walker, 1984 Sedgwick and Goodwin, 1985). This is due to a deficiency in umu D activity in these Salmonella strains (Herrera et... 

Herrera, G., Urios, A., Alexandre, V, and Blanco, M., (1988). UV light induced mutability in Salmonella strains containing the limit DC or the mite AB operon evidence for a limit C function. Mutation Res. 198 9-13. 

Also Enterobacteria are able to synthesize unsaturated fatty acids and to incorporate these into the lipid A component. Thus, when grown at low temperature (10- 15°C) E. coli (143), Salmonella spp. (142), P. mirabilis (37), and Y. enterocolitica (145) are incorporated into the lipid A component unsaturated fatty acids that are not present in LPS of bacteria grown at 370 C. For E. coli and Salmonella strains grown at low temperatures, it was found that (Z)-A9-hexadecenoic acid (A9-16 1) was incorporated at the expense of 12 0 (142,143), however, not quantitatively. Further investigations of these lipid A by l.d.-m.s. revealed that the unsaturated fatty acid specifically replaced the 12 0 residue in 14 0[3-6>( 12 0)] that is bound to GlcN(II) (37). A similar effect of thermoadaptation, resulting in the formation of amide-bound 14 0[3-6>(A9-16 1)], was detected in P. mirabilis and Y. enterocolitica (145). 

De Flora S, Camoirano A, Zanacchi P, et al. 1984. Mutagenicity testing with TA97 and TA102 of 30 DNA-damaging compounds, negative with other Salmonella strains. Mutat Res 134 159-165. 

Kerklaan PRM, Zoetemelk CEM, Mohn GR. 1985. Mutagenic activity of various chemicals in Salmonella strain TA100 and glutathione-deficient derivatives On the role of glutathione in the detoxification or activation of mutagens inside bacterial cells. Biochem Pharmacol 34 2151-2156. 

Zoetemelk CEM, Mohn GR, Van DerGen A, et al. 1987. 1,2-Dibromo compounds Their mutagenicity in Salmonella strains differing in glutathione content and their alkylating potential. 

At least some of the metals, such as chromate, mutate the Salmonella strains when salts in the medium are lowered (S. Rogers and G. Lofroth, pers. comm.). 

Recombinant vaccines Vaccines that can deliver and penetrate intestinal wall via M cells Tetanus toxin, Salmonella strains, vaccinia virus vector... 

Enzyme preparations that can convert a-D-mannopyranosyl or 6-deoxy-a-D-Zt/xo-hexopyranosyl-4-ulose esters of guanosine 5 -pyro-phosphate into the /3-L-fucopyranosyl ester were obtained from Aerobacter aerogenes,99 432 Escherichia coli,100 Salmonella strains,433 higher plants,92 and animal tissues.434 Further purification of these enzymes will be necessary for mechanistic studies. 

Dideoxyhexoses. Several bacterial antigenic determinants with the general structure of 3,6-dideoxyhexoses occur in the cell wall of Pasteurella and Salmonella strains. Most of the transformations reported so far occur as cytidine nucleotides (see Table I, References 15, 16, 17, 18, 19). Here, again the first step is the transformation of the cytidine diphospho-linked glucose into its corresponding 4-keto derivative. By at least two distinct steps, requiring NADPH, reduction to several different 3,6-dideoxyhexoses have been reported. One 3,6-dideoxyhexose CDP-tyvelose (3,6-dideoxy-D-arabino hexose) is formed by a specific 2-epimer-ase from CDP-paratose (24). 

Figure I. Linkages of the KDO region of LPSfrom Salmonella strains as proposed in...

Figure 4. Effect of reflux time, amino acid (glycine or alanine), and Salmonella strain on the mutagenic activity formed in model reaction systems of creatinine (1.25 g), o-glucose (0.8 g), and amino acid (1.07 g) in diethylene glycol-water (6 1 v/v).

The test is based on the capability of genotoxic agents to induce the umuC-gene in the Salmonella strain in response to genotoxic lesions in the DNA. The induction of the umuC-gene is thus a measure for the genotoxic potential of the sample. 

The untreated SRC-II was tested at five concentrations with Salmonella strains TA 98 and TA 100, generally considered the most sensitive strains. In the results indicated in Table III, an increase in the number of revertants greater than two times the background (no SRC-II feed or product) is sometimes considered to indicate a definite positive (mutagenic) response. The plates which showed a positive response by this criteria are underlined. 

The author acknowledges the expert technical assistance of George Sfeir, Mary Jones and Cathleen Slade. The Salmonella strains were kindly provided by Professor Bruce Ames. Aroclor 1254 was generously provided by Montsanto Co., and 3,2 -dimethyl-4-amino-biphenyl was generously supplied by the National Cancer Institute. 

Aside from the expression of histidine mutations that are easily detected, other properties have been built into the Salmonella strains by mutation to increase their sensitivity. The strains cure defective in DNA excision repair (uvrB). In this case, the increased sensitivity probably is due to the failure to remove some DNA adducts that could lead to mutation. The strains also possess a mutation (rfa) that removes part of the lipopolysaccharide barrier of the bacterial cell wall and thereby makes the cells more permeable to some chemicals. Finally, Salmonella strains TA98 and TA100 contain the R-factor plasmid pkMIOl,277 which increases sensitivity probably by increasing the activity of an error-prone DNA-repair system. 

Witmer C, Cooper K, Kelly J. 1982. Effects of plating efficiency and lowered concentration of salts on mutagenicity assays with Ames Salmonella strains. Adv Exp Med Biol 136B 1271-1284. 

In the Ames assay, 1,1 -dichloroethane was nonmutagenic in Salmonella strains TA97, TA98, TA100, and TA102 (Nohmi et al. 1985). The compound was tested with and without metabolic activation. 

Ames Salmonella (strains unstated) 0.3-15 mg/plate Negative, in the presence and absence of metabolic activation. This is an unpublished study described in a secondary source and no further information is available. 5... 

Acetonitrile was tested for mutagenicity in the Salmonella/microsome preincubation assay. The tests were conducted using up to five Salmonella strains and in the presence and absence of rat or hamster liver S-9. All tests were negative for mutagenicity... 

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