Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 7 de 7
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
2.
Biosecur Bioterror ; 12(1): 49-62, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24552362

RESUMO

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. One of the complicating factors associated with LFAs is the use of antibodies of poor affinity and specificity that cross-react with near neighbors or that bind to plant lectins, which are capable of nonspecifically cross-linking the capture and detector antibodies. Because of the critical need to promote public safety and public health, we conducted a comprehensive laboratory evaluation of a commercial LFA for the rapid detection of abrin. This study was conducted using comprehensive inclusivity and exclusivity panels of abrin and near-neighbor plant materials, along with panels of lectins, related proteins, white powders, and environmental background material, to determine the sensitivity, specificity, limit of detection, dynamic range, and repeatability of the assay for the specific intended use of evaluating suspicious white powders and environmental samples for the presumptive presence of abrin.


Assuntos
Abrina/isolamento & purificação , Pós/química , Kit de Reagentes para Diagnóstico/normas , Terrorismo Químico , Pós/intoxicação , Fitas Reagentes , Sensibilidade e Especificidade , Estados Unidos
3.
Plasmid ; 69(3): 257-62, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23396145

RESUMO

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. pACK5 is comprised of two regions, one with 85% identity at the nucleotide level to a region of pWBG1773 and another region with an ORF that shares no significant similarity to sequences previously described in GenBank. pACK2 encodes proteins for cadmium resistance and enhanced biofilm formation. The similarities at the nucleotide level among regions of the plasmids of S. simulans bv. staphylolyticus suggest that these plasmids have undergone multiple intermolecular rearrangements.


Assuntos
Biofilmes , DNA Bacteriano/genética , Plasmídeos/genética , Staphylococcus/genética , Proteínas de Bactérias/genética , Sequência de Bases , Compostos de Cádmio/farmacologia , Replicação do DNA , Rearranjo Gênico , Fases de Leitura Aberta , Óperon , Origem de Replicação , Homologia de Sequência do Ácido Nucleico , Staphylococcus/efeitos dos fármacos , Staphylococcus/fisiologia , Sulfatos/farmacologia
4.
Appl Environ Microbiol ; 76(20): 6944-6, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-20729317

RESUMO

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.


Assuntos
Lisostafina/antagonistas & inibidores , Peptidoglicano/metabolismo , Staphylococcus/enzimologia , Parede Celular
5.
Appl Environ Microbiol ; 75(19): 6205-10, 2009 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19684178

RESUMO

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. The peptidoglycan from each strain was hydrolyzed using the streptococcolytic phage lysin B30, and the resulting muropeptides were separated by reverse-phase high-pressure liquid chromatography, labeled with 4-sulfophenyl isothiocyanate, and analyzed by tandem mass spectrometry in the negative-ion mode. It was determined that Zif alters the peptidoglycan by increasing the proportion of cross bridges containing three L-alanines instead of two. This modification decreased binding of the recombinant target recognition domain of zoocin A to peptidoglycan. Zif-modified peptidoglycan also was less susceptible to hydrolysis by the recombinant catalytic domain of zoocin A. Thus, Zif is a novel FemABX-like immunity factor because it provides resistance to a bacteriolytic endopeptidase by lengthening the peptidoglycan cross bridge rather than by causing an amino acid substitution.


Assuntos
Antibacterianos/biossíntese , Antibacterianos/farmacologia , Proteínas de Bactérias/fisiologia , Farmacorresistência Bacteriana , Streptococcus equi/efeitos dos fármacos , Streptococcus equi/genética , Proteínas de Bactérias/biossíntese , Proteínas de Bactérias/genética , Proteínas de Bactérias/farmacologia , Parede Celular/química , Cromatografia Líquida de Alta Pressão , Mucoproteínas/metabolismo , Peptidoglicano/química , Peptidoglicano/isolamento & purificação , Streptococcus equi/metabolismo , Espectrometria de Massas em Tandem , Proteínas Virais/metabolismo
6.
Appl Environ Microbiol ; 75(1): 72-7, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-18978086

RESUMO

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. In order to distinguish among possible structures for these muropeptides, they were N-terminally labeled with 4-sulfophenyl isothiocyanate (SPITC) and analyzed by tandem MS in the negative-ion mode. This novel application of SPITC labeling and MS/MS analysis can be used to analyze the structure of peptidoglycans and to determine the sites of action of other peptidoglycan hydrolases.


Assuntos
Proteínas de Bactérias/metabolismo , Benzenossulfonatos/metabolismo , Isotiocianatos/metabolismo , Espectrometria de Massas , Peptidoglicano/metabolismo , Coloração e Rotulagem/métodos , Streptococcus equi/enzimologia
7.
FEMS Microbiol Lett ; 249(2): 227-31, 2005 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-16006076

RESUMO

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. Based on both its function and its similarity to femAB, this gene is a member of the femABX-like immunity gene family. Furthermore, this is the first example of a femABX-like immunity gene that is not linked to the gene for the bacteriolytic enzyme against which it specifies immunity.


Assuntos
Plasmídeos , Staphylococcus/genética , Proteínas de Bactérias/genética , Sequência de Bases , Primers do DNA , DNA Bacteriano/genética , Resistência Microbiana a Medicamentos/genética , Endopeptidases/genética , Fases de Leitura Aberta , Mapeamento por Restrição
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...