Comprehensive laboratory evaluation of a specific lateral flow assay for the presumptive identification of abrin in suspicious white powders and environmental samples.

Abrin is a heterodimeric toxin present in the seeds of the Abrus precatorius plant. The easily obtainable seeds can yield a highly toxic product that can be used in various types of biocrimes and terrorism-related activities, including "white-powder" letters. Although the vast majority of these threats are hoaxes, the lack of rapid and reliable detection assays for abrin, such as lateral flow assays (LFAs), can be an impediment to accurate and rapid hazard assessment.

Complete nucleotide sequences of plasmids pACK2 and pACK5 from Staphylococcus simulans biovar staphylolyticus.

Staphylococcus simulans biovar staphylolyticus contains five plasmids, designated pACK1-pACK5. Recently, the nucleotide sequences of three of these plasmids, pACK1, pACK3, and pACK4, were reported. In order to complete the characterization of these five plasmids, the nucleotide sequences of the two remaining plasmids, pACK2 (37683 bp) and pACK5 (3191 bp), were determined.

Inhibition of the activity of both domains of lysostaphin through peptidoglycan modification by the lysostaphin immunity protein.

Resistance to lysostaphin, a staphylolytic glycylglycine endopeptidase, is due to a FemABX-like immunity protein that inserts serines in place of some glycines in peptidoglycan cross bridges. These modifications inhibit both binding of the recombinant cell wall targeting domain and catalysis by the recombinant catalytic domain of lysostaphin.

Zif, the zoocin A immunity factor, is a FemABX-like immunity protein with a novel mode of action.

Producer cell immunity to the streptococcolytic enzyme zoocin A, which is a D-alanyl-L-alanine endopeptidase, is due to Zif, the zoocin A immunity factor. Zif has high degrees of similarity to MurM and MurN (members of the FemABX family of proteins), which are responsible for the addition of amino acids to cross bridges during peptidoglycan synthesis in streptococci. In this study, purified peptidoglycans from strains with and without zif were compared to determine how Zif modifies the peptidoglycan layer to cause resistance to zoocin A.

Use of 4-sulfophenyl isothiocyanate labeling and mass spectrometry to determine the site of action of the streptococcolytic peptidoglycan hydrolase zoocin A.

Zoocin A is a streptococcolytic peptidoglycan hydrolase with an unknown site of action that is produced by Streptococcus equi subsp. zooepidemicus 4881. Zoocin A has now been determined to be a d-alanyl-l-alanine endopeptidase by digesting susceptible peptidoglycan with a combination of mutanolysin and zoocin A, separating the resulting muropeptides by reverse-phase high-pressure liquid chromatography, and analyzing them by mass spectrometry (MS) in both the positive- and negative-ion modes to determine their compositions.

Plasmid-specified FemABX-like immunity factor in Staphylococcus sciuri DD 4747.

A plasmid from Staphylococcus sciuri DD 4747 had three open reading frames: a replication gene, an N-acetylmuramyl-l-alanine amidase-like gene, and a gene similar to the lysostaphin endopeptidase resistance gene (epr/lif). The epr-like gene was introduced into S. aureus RN4220; the recombinant strain was more resistant to lysostaphin endopeptidase and its cell wall peptidoglycan contained more serines and fewer glycines than the parental strain with the shuttle vector alone.