Toxin-antitoxin systems are ubiquitous and have been implicated in persistence, the multidrug tolerance of bacteria, biofilms, and, by extension, most chronic infections. However, their purpose, apparent redundancy, and coordination remain topics of debate. Our model relates molecular mechanisms to population dynamics for a large class of toxin-antitoxin systems and suggests answers to several ...

In previous work on the denaturation of antibody, studies have been made of some of the factors influencing the inactivation of diphtheria antitoxin in urea solutions (1, 2). A quantitative formulation of a simple kinetic theory was found to fit satisfactorily the experimental data and to offer a reasonable explanation of the deviation of the inactivation from simple first order behavior (2). I...

The specific rate of inactivation of antitoxin in urea solutions, as measured by the Römer neutralization test with toxin, has been shown to be independent of the concentration of protein under the conditions studied. The amount of precipitate obtained in the quantitative precipitation test with toxin, however, increases greatly with increasing protein concentration during denaturation. The tim...

The HigA2 antitoxin and the HigBA2 toxin-antitoxin complex from Vibrio cholerae were crystallized in complex with their operator box. Screening of 22 different DNA duplexes led to two crystal forms of HigA2 complexes and one crystal form of a HigBA2 complex. Crystals of HigA2 in complex with a 17 bp DNA duplex belong to space group P3221, with unit-cell parameters a = b = 94.0, c = 123.7 Å, and...

BACKGROUND Only Clostridium botulinum strain IBCA10-7060 produces the recently described novel botulinum neurotoxin type H (BoNT/H). BoNT/H (N-terminal two-thirds most homologous to BoNT/F and C-terminal one-third most homologous to BoNT/A) requires antitoxin to toxin ratios ≥1190:1 for neutralization by existing antitoxins. Hence, more potent and safer antitoxins against BoNT/H are needed. M...

Toxin-antitoxin (TA) loci consist of two genes in an operon, encoding a stable toxin and an unstable antitoxin. The expression of toxin leads to cell growth arrest and sometimes bacterial death, while the antitoxin prevents the cytotoxic activity of the toxin. In this study, we show that the chromosome of Yersinia pestis, the causative agent of plague, carries 10 putative TA modules and two sol...

JANSEN, B. C. The toxic antigenic factors produced by Clostridium botulinum types C and D. Onderstepoort ]. vet Res., 38 (2), 93-98 (1971). The toxic factors produced by Clostridium botulinum (Van Ermengem, 1896), types C and D were determined. Monospecific antisera were prepared against the different factors. It was shown that type Coc produces factors C" C2 and D; type C f3 produces factor C ...

Toxin-antitoxin (TA) systems are found on both bacterial plasmids and chromosomes, but in most cases their functional role is unclear. Gene knockouts often yield limited insights into functions of individual TA systems because of their redundancy. The well-characterized F-plasmid-based CcdAB TA system is important for F-plasmid maintenance. We have isolated several point mutants of the toxin Cc...

Biofilms are well known for their extreme tolerance to antibiotics. Recent experimental evidence has indicated the existence of a small fraction of specialized persister cells may be responsible for this tolerance. Although persister cells seem to exist in planktonic bacterial populations, within a biofilm the additional protection offered by the polymeric matrix allows persister cells to evade...