PMID- 349567
OWN - NLM
STAT- MEDLINE
DCOM- 19780715
LR  - 20190501
IS  - 0027-8424 (Print)
IS  - 1091-6490 (Electronic)
IS  - 0027-8424 (Linking)
VI  - 75
IP  - 3
DP  - 1978 Mar
TI  - Isolation and characterization of enterotoxin-deficient mutants of Escherichia 
      coli.
PG  - 1384-8
AB  - The genes controlling the production of two types of enterotoxin of Escherichia 
      coli, one heat-labile (LT) and the other heat-stable (ST), are found on plasmids. 
      The absence of a direct selection procedure has made it difficult to isolate 
      mutants affecting toxin production. However, the availability of a naturally 
      occurring "recombinant" plasmid, carrying genes for LT and ST formation and also 
      for resistance to tetracycline, streptomycin, and sulfonamides, made it possible 
      to use comutagenesis with N-methyl-N'-nitro-N-nitrosoguanidine to enrich for such 
      mutants. We have isolated and characterized 58 LT- mutants and 7 ST- mutants. 
      Among the LT- group we found amber mutants, temperature-sensitive mutants (most 
      of which produce unusually heat-labile LT), and "leaky" mutants with reduced LT 
      activity. The majority of the tested LT- mutants produced immunologically 
      crossreacting material, in most cases in wild-type amounts. Among all 17 of the 
      LT- mutants that could be transferred, the mutation was found to be on the 
      plasmid. In contrast, only one of four transferrable ST- mutants appeared to be a 
      plasmid mutant.
FAU - Silva, M L
AU  - Silva ML
FAU - Maas, W K
AU  - Maas WK
FAU - Gyles, C L
AU  - Gyles CL
LA  - eng
PT  - Journal Article
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - Proc Natl Acad Sci U S A
JT  - Proceedings of the National Academy of Sciences of the United States of America
JID - 7505876
RN  - 0 (Bacterial Toxins)
RN  - 0 (Enterotoxins)
SB  - IM
MH  - Bacterial Toxins/*genetics/immunology
MH  - Chromosome Mapping
MH  - Cross Reactions
MH  - Enterotoxins/*genetics
MH  - Escherichia coli/*genetics/isolation & purification
MH  - Genes
MH  - Mutation
MH  - Plasmids
PMC - PMC411476
EDAT- 1978/03/01 00:00
MHDA- 1978/03/01 00:01
PMCR- 1978/09/01
CRDT- 1978/03/01 00:00
PHST- 1978/03/01 00:00 [pubmed]
PHST- 1978/03/01 00:01 [medline]
PHST- 1978/03/01 00:00 [entrez]
PHST- 1978/09/01 00:00 [pmc-release]
AID - 10.1073/pnas.75.3.1384 [doi]
PST - ppublish
SO  - Proc Natl Acad Sci U S A. 1978 Mar;75(3):1384-8. doi: 10.1073/pnas.75.3.1384.