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A Toussaint

Publications and source records attributed to A Toussaint.

At least 55 records · Page 3Linked to original sources
PubMed1985

Bacteriocin-resistant mutants of Erwinia chrysanthemi: possible involvement of iron acquisition in phytopathogenicity.

A series of bacteriocin-resistant mutants of Erwinia chrysanthemi 3937JRH were unable to elicit soft-rot symptoms on saintpaulia plants. The loss of pathogenicity was correlated with the disappearance of one to three outer membrane polypeptides (molecular weights, about 80,000 to 90,000) whose production in wild-type strains was greatly enhanced under iron-limited growth conditions. The mutants did not exhibit altered extracellular pectinolytic or cellulolytic activities.

Bacterial Outer Membrane Proteins↗
PubMed1983

The products of gene A of the related phages Mu and D108 differ in their specificities.

By recombination between different mutants of mutator phages Mu and D108, we isolated a set of viable hybrids. The structure of the hybrids was analyzed by digestion with different restriction enzymes. Genetic studies show that hybrids which carry the left end of the Mu genome complement a mini-Mu deleted from within the A gene as well as Mu while hybrids with the left end of the D108 genome or D108 do not. Vice versa, hybrids with the left end of the D108 genome or D108, but not hybrids with the left end of the Mu genome or Mu complement a mini-D108 deleted from within the A gene. The nucleotide sequence of the A gene of Mu and its equivalent on D108 are mainly similar except on their left end. These observations demonstrate that the two pA products, although only partially different, have different specificities.

Bacteriophage mu↗
PubMed1983

In vivo cloning of Erwinia carotovora genes involved in the catabolism of hexuronates.

Using the RP4::mini-Mu pULB113 plasmid, an RP4 derivative carrying a deleted Mu prophage which allows the plasmid to pick up any chromosomal DNA segment to form R' plasmids, we cloned all of the genes of Erwinia carotovora involved in the catabolism of the hexuronates and in the transport of these substrates. With the R' plasmids we isolated, we performed complementation analysis and found that, in the Erwinia carotovora strain we used, the genes involved in the catabolism of the hexuronates are clustered in four regions of the chromosome. This genetic organization is compared with that of Escherichia coli K-12.

Chromosome Mapping↗
PubMed1983

Utilization of plasmid pULB113 (RP4::mini-Mu) to construct a linkage map of Erwinia carotovora subsp. chrysanthemi.

We report experimental evidence that pULB113, an RP4::mini-Mu plasmid, mediates chromosome transfer in a strain of Erwinia carotovora subsp. chrysanthemi which does not accept the F episome. This allowed us to construct a genetic map of that strain by measuring the frequencies of cotransfer of different markers (thy, leu, pro, [his, trp], thyA, rpsL, ile).

Chromosome Mapping↗
PubMed1983

Chromosome transfer and R-prime plasmid formation mediated by plasmid pULB113 (RP4::mini-Mu) in Alcaligenes eutrophus CH34 and Pseudomonas fluorescens 6.2.

Plasmid pULB113 (RP4::mini-Mu), which contains the mini-Mu transposon, promoted both homologous and heterologous gene transfer from Pseudomonas fluorescens 6.2 and Alcaligenes eutrophus CH34. Homologous gene transfer in P. fluorescens 6.2 and A. eutrophus CH34 occurred at a frequency of 10(-4) to 10(-5), and recombinants inherited unselected recessive markers, suggesting a process of chromosome mobilization. Loci involved in autotrophic growth were among those transferred in A. eutrophus. In heterospecific matings, markers were transferred from P. fluorescens to A. eutrophus, Salmonella typhimurium LT2, and Escherichia coli, from A. eutrophus to P. fluorescens, and from Erwinia carotovora subsp. chrysanthemi to A. eutrophus. Heterospecific matings resulted in the formation of R-prime plasmids at frequencies of 10(-7) to 10(-4) per transferred plasmid. When S. typhimurium was the recipient, we observed R-prime plasmids with both restriction-proficient and restriction-deficient strains, although restriction markedly affected the frequency of transfer of pULB113. R-prime plasmids were quite stable, but lost the transposed marker more easily in a rec+ background than in a recA background, suggesting excision of transposed material by reciprocal recombination between flanking copies of mini-Mu. R-prime plasmids could be transferred easily into different recipients and were used in complementation studies. PstI restriction digests of four R-prime plasmids carrying P. fluorescens 6.2 DNA showed a number of additional bands, suggesting that several genes were transposed together with the selected marker on the plasmid.

Alcaligenes↗
PubMed1982

Localisation of mini-Mu in its replication intermediates.

We have located Mu delta 26 sequences straddling the forks in DNA structures which appear during Mu delta 26 replication, i.e., keys, pending keys, dumb- bells , partially fused circles, and asymmetrical forks. This brings additional evidence that these structures are mini-Mu replication intermediates. The possible relationship between these structures and those predicted by the different models formulated to explain transposition in procaryotes is discussed.

Coliphages↗
PubMed1982

Formation of F'trp plasmids in Escherichia coli K12.

From strains carrying two different F-prime factors, we recovered F' derivatives that acquired the trp chromosomal region. These F'trp plasmids can be isolated at a frequency of 10(-5) to 10(-6). They were characterized genetically by looking at the size of the trp segment they acquired and at the location of that segment in the parental F' plasmid. Results are discussed in relationship to possible transposition mechanisms.

Chromosome Mapping↗
PubMed1981

Genetic analysis of mu or mini-mu containing F' pro lac episomes after prophage induction.

We have investigated the fate of different F pro lac episomes carrying a Mu or mini-Mu, after induction of the Mu or mini-Mu prophage, by looking at the frequencies of transfer of the episome and of one chromosomal marker. During the first 10 min after induction the frequency of chromosome mobilization increases while the frequency of episome transfer decreases. This suggests that the F interacts with the chromosome through some kind of Mu mediated process. Later the transfer of both the episome and chromosomal markers is inhibited. Possible reasons for this inhibition are discussed.

Bacteriophage mu↗
PubMed1981

Genetic mapping of a mutation conferring sensitivity to bacteriophage Mu in Salmonella typhimurium LT2.

Two strains of Salmonella typhimurium LT2, SA1475 and MA411, were fortuitously found to be sensitive to bacteriophage Mu. The Mu-sensitivity allele of SA1475 was called musA1 and shown to be linked to the histidine operon both in conjugation and transduction experiments. The Mus allele of MA411 was unlinked to the his region and was tentatively designated musB2. Strains carrying large deletions of the his operon were also tested for Mu sensitivity; those of which the his-rib region is deleted were also sensitive to Mu. Transduction data led to the order zee-2 hisOGDCBAHFIE gnd musA. An Hfr injecting the his operon early (HfrK9) an carrying hisG9424::Tn10 delta 4 delta 11 and musA1 was isolated; this Hfr made it possible to introduce the Mus character into most derivatives of S. typhimurium LT2. Since strain SA1475 is resistant to bacteriophage P1, it could be used to select a new P1-Mu hybrid which has the host range of Mu and the transduction properties of P1.

Alleles↗