Lysozyme, hydrochloride

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Remarks:

Type of genotoxicity: gene mutation

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

The test parameters documented do not totally comply with the specific testing guideline, but they are sufficient to accept the data. The test was conducted according to internationally accepted testing guidelines. Details about the read across approach are reported in the summary.

Data source

Reference

Reference Type:

publication

Title:

Safety Evaluation of a Lipase Expressed in Aspergillus oryzae.

Author:

Greenough R.J., Perry C.J. and Stavnsbjerg M.

Year:

1996

Bibliographic source:

Fd Chem. Toxic. Vol. 34, No. 2, pp. 161-166, 1996

Materials and methods

Principles of method if other than guideline:

The test substance was examined for mutagenic activity using Salmonella typhimurium strains TA1535, TA100, TA1537 and TA98 and Escherichia coli WP2uvrA, both in presence and in absence if metabolic activation. Bacteria were exposed to five doses of test material in a phosphate buffered nutrient broth for 3 hr.

GLP compliance:

not specified

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Lipase

IUPAC Name:

Lipase

Method

Species / strain

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2

Metabolic activation:

with and without

Metabolic activation system:

a liver preparation from male rats pretreated with Aroclor 1254 and cofactors required for mixed function oxidase activity (S-9 mix)

Test concentrations with justification for top dose:

Bacteria were exposed to five doses of test material from 0.1 to 10 mg/ml incubation mixture at half-log intervals.

Details on test system and experimental conditions:

Lipase activity was removed from the test material by ultrafiltration before testing because of its destructive action on the metabolic activation system (S-9) and the bacterial cell wall.
A liquid culture assay was used.
Bacteria were exposed to five doses of test material in a phosphate buffered nutrient broth for 3 hr.
After incubation the test substance was removed by centrifugation before plating.
The numbers of revertants to prototrophy and viable cells were estimated.

The sensitivity of the individual bacterial strains was confirmed by notable increases in the number of revertant colonies induced in similar liquid conditions by diagnostic mutagens.

Results and discussion

Test results

Species / strain:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Additional information on results:

No dose-related increases in revertants to phototrophy were obtained in any of the tests performed; all results were confirmed in an independent experiment and it was concluded that there were no indications of mutagenic activity in the presence or absence of metabolic activation.

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative

No indications of mutagenic activity in the presence or absence of metabolic activation.

Executive summary:

The test substance was examined for mutagenic activity using Salmonella typhimurium strains TA1535, TA100, TA1537 and TA98 and Escherichia coli WP2uvrA. The test substance activity was removed from the test material by ultrafiltration before testing because of its destructive action on the metabolic activation system (S-9) and the bacterial cell wall. A liquid culture assay was used.

Bacteria were exposed to five doses of test material in a phosphate buffered nutrient broth for 3 hr. After incubation the test substance was removed by centrifugation before plating. The numbers of revertants to prototrophy and viable cells were estimated.

The sensitivity of the individual bacterial strains was confirmed by notable increases in the number of revertant colonies induced in similar liquid conditions by diagnostic mutagens.

No dose-related increases in revertants to phototrophy were obtained in any of the tests performed; all results were confirmed in an independent experiment and it was concluded that there were no indications of mutagenic activity in the presence or absence of metabolic activation.

Conclusion

No indications of mutagenic activity in the presence or absence of metabolic activation.