Lipidation of Class IV CdiA Effector Proteins Promotes Target Cell Recognition during Contact-Dependent Growth Inhibition

primers
Contact-dependent growth inhibition (CDI) systems enable the direct transfer of protein toxins between competing Gram-negative bacteria. CDI+ strains produce cell surface CdiA effector proteins that bind specific receptors on neighboring bacteria to initiate toxin delivery. Three classes of CdiA effectors that recognize different outer membrane protein receptors have been characterized in Escherichia coli to date. Here, we describe a fourth effector class that uses the lipopolysaccharide (LPS) core as a receptor to identify target bacteria. Selection for CDI-resistant target cells yielded waaF and waaP “deep-rough” mutants, which are unable to synthesize the full LPS core. The CDI resistance phenotypes of other waa mutants suggest that phosphorylated inner-core heptose residues form a critical CdiA recognition epitope. Class IV cdi loci also encode putative lysyl acyltransferases (CdiC) that are homologous to enzymes that lipidate repeats-in-toxin (RTX) cytolysins.
We found that catalytically active CdiC is required for full target cell killing activity, and we provide evidence that the acyltransferase appends 3-hydroxydecanoate to a specific Lys residue within the CdiA receptor-binding domain. We propose that the lipid moiety inserts into the hydrophobic leaflet of lipid A to anchor CdiA interactions with the core oligosaccharide. Thus, LPS-binding CDI systems appear to have co-opted an RTX toxin-activating acyltransferase to increase the affinity of CdiA effectors for the target cell outer membrane.
IMPORTANCE Contact-dependent growth inhibition (CDI) is a common form of interbacterial competition in which cells use CdiA effectors to deliver toxic proteins into their neighbors. CdiA recognizes target bacteria through specific receptor molecules on the cell surface. Here, we describe a new family of CdiA proteins that use lipopolysaccharide as a receptor to identify target bacteria.
Target cell recognition is significantly enhanced by a unique fatty acid that is appended to the receptor-binding region of CdiA. We propose that the linked fatty acid inserts into the target cell outer membrane to stabilize the interaction. The CdiA receptor-binding region appears to mimic the biophysical properties of polymyxins, which are potent antibiotics used to disrupt the outer membranes of Gram-negative bacteria.

Quantitative proteomics reveals that dormancy-related proteins mediate the attenuation in mycobacterium strains

 

Although members of the Mycobacterium tuberculosis complex (MTBC) exhibit high similarity, they are characterized by differences with respect to virulence, immune response, and transmissibility. To understand the virulence of these bacteria and identify potential novel therapeutic targets, we systemically investigated the total cell protein contents of virulent H37Rv, attenuated H37Ra, and avirulent M. bovis BCG vaccine strains at the log and stationary phases, based on tandem mass tag (TMT) quantitative proteomics. Data analysis revealed that we obtained deep-coverage protein identification and high quantification.
Although 272 genetic variations were reported in H37Ra and H37Rv, they showed very little expression difference in log and stationary phase. Quantitative comparison revealed H37Ra and H37Rv had significantly dysregulation in log phase (227) compared with stationary phase (61). While BCG and H37Rv, and BCG and H37Ra showed notable differences in stationary phase (1171 and 1124) with respect to log phase (381 and 414). In the log phase, similar patterns of protein abundance were observed between H37Ra and BCG, whereas a more similar expression pattern was observed between H37Rv and H37Ra in the stationary phase.
Bioinformatic analysis revealed that the upregulated proteins detected for H37Rv and H37Ra in log phase were virulence-related factors. In both log and stationary phases, the dysregulated proteins detected for BCG, which have also been identified as M. tuberculosis response proteins under dormancy conditions. We accordingly describe the proteomic profiles of H37Rv, H37Ra, and BCG, which we believe will potentially provide a better understanding of H37Rv pathogenesis, H37Ra attenuation, and BCG immuno protection.

Human Monoclonal Ant

 primers

primers

ibodies against NS1 Protein Protect against Lethal West Nile Virus Infection

 

Envelope protein-targeted vaccines for flaviviruses are limited by concerns of antibody-dependent enhancement (ADE) of infections. Nonstructural protein 1 (NS1) provides an alternative vaccine target that avoids this risk since this protein is absent from the virion. Beyond its intracellular role in virus replication, extracellular forms of NS1 function in immune modulation and are recognized by host-derived antibodies. The rational design of NS1-based vaccines requires an extensive understanding of the antigenic sites on NS1, especially those targeted by protective antibodies. Here, we isolated human monoclonal antibodies (MAbs) from individuals previously naturally infected with WNV, mapped their epitopes using structure-guided mutagenesis, and evaluated their efficacy in vivo against lethal WNV challenge.
The most protective epitopes clustered at three antigenic sites that are exposed on cell surface forms of NS1: (i) the wing flexible loop, (ii) the outer, electrostatic surface of the wing, and (iii) the spaghetti loop face of the β-ladder. One additional MAb mapped to the distal tip of the β-ladder and conferred a lower level of protection against WNV despite not binding to NS1 on the surface of infected cells. Our study defines the epitopes and modes of binding of protective anti-NS1 MAb antibodies following WNV infection, which may inform the development of NS1-based countermeasures against flaviviruses.
IMPORTANCE Therapeutic antibodies against flaviviruses often promote neutralization by targeting the envelope protein of the virion. However, this approach is hindered by a possible concern for antibody-dependent enhancement of infection and paradoxical worsening of disease. As an alternative strategy, antibodies targeting flavivirus nonstructural protein 1 (NS1), which is absent from the virion, can protect against disease and do not cause enhanced infection.
Here, we evaluate the structure-function relationships and protective activity of West Nile virus (WNV) NS1-specific monoclonal antibodies (MAbs) isolated from the memory B cells of a naturally infected human donor. We identify several anti-NS1 MAbs that protect mice against lethal WNV challenge and map their epitopes using charge reversal mutagenesis. Antibodies targeting specific regions in the NS1 structure could serve as the basis for countermeasures that control WNV infection in humans.

Discovery of Novel Chromone Derivatives Containing a Sulfonamide Moiety as Anti-ToCV Agents through the Tomato Chlorosis Virus Coat Protein-Oriented Screening Method

 

A number of novel chromone derivatives containing sulfonamide moieties were designed and synthesized, and the activity of compounds against tomato chlorosis virus (ToCV) was assessed using the ToCVCP-oriented screening method. Comparative molecular field analysis (CoMFA) and comparative molecular similarity index analysis (CoMSIA) models were established based on the dissociation constant  values of the target compounds, and compound was designed and synthesized with the aid of CoMFA and CoMSIA models.
The study of affinity interaction indicated that compound  exhibited excellent affinity with ToCVCP with a d value of 0.11 μM, which was better than that of the positive control agents xiangcaoliusuobingmi (0.44 μM) and ningnanmycin (0.79 μM). In addition, the in vivo  inhibitory effect of compound  on the ToCVCP gene was evaluated by the quantitative real-time polymerase chain reaction. ToCVCP gene expression levels of the compound <b>35</b> treatment group were reduced by 67.2%, which was better than that of the positive control agent ningnanmycin (59.5%). Therefore, compound  can be used as a potential anti-ToCV drug in the future.

Human Creatine kinase BB isoenzyme (CK-BB) ELISA Kit

EK12245 96Т
EUR 799

Human Creatine kinase BB isoenzyme (CK-BB) ELISA Kit

AE63302HU-48Tests 48 Tests
EUR 325
Description: Human (Homo sapiens)

Human Creatine kinase BB isoenzyme (CK-BB) ELISA Kit

AE63302HU-96Tests 96 Tests
EUR 610
Description: Human (Homo sapiens)

Human creatine kinase BB isoenzyme (CK-BB) ELISA kit

CSB-EQ027522HU-24T 1 plate of 24 wells
EUR 198
Description: Quantitativesandwich ELISA kit for measuring Human creatine kinase BB isoenzyme (CK-BB) in samples from serum, plasma, tissue homogenates. A new trial version of the kit, which allows you to test the kit in your application at a reasonable price.

Human creatine kinase BB isoenzyme (CK-BB) ELISA kit

1-CSB-EQ027522HU
  • Ask for price
  • Ask for price
  • Ask for price
  • 1 plate of 96 wells
  • 10 plates of 96 wells each
  • 5 plates of 96 wells each
Description: Quantitativesandwich ELISA kit for measuring Human creatine kinase BB isoenzyme (CK-BB) in samples from serum, plasma, tissue homogenates. Now available in a cost efficient pack of 5 plates of 96 wells each, conveniently packed along with the other reagents in 5 separate kits.

Mouse creatine kinase BB isoenzyme (CK-BB) ELISA kit

CSB-EQ027522MO-24T 1 plate of 24 wells
EUR 198
Description: Quantitativesandwich ELISA kit for measuring Mouse creatine kinase BB isoenzyme (CK-BB) in samples from serum, plasma, tissue homogenates. A new trial version of the kit, which allows you to test the kit in your application at a reasonable price.

Mouse creatine kinase BB isoenzyme (CK-BB) ELISA kit

1-CSB-EQ027522MO
  • Ask for price
  • Ask for price
  • Ask for price
  • 1 plate of 96 wells
  • 10 plates of 96 wells each
  • 5 plates of 96 wells each
Description: Quantitativesandwich ELISA kit for measuring Mouse creatine kinase BB isoenzyme (CK-BB) in samples from serum, plasma, tissue homogenates. Now available in a cost efficient pack of 5 plates of 96 wells each, conveniently packed along with the other reagents in 5 separate kits.

Human Creatine Kinase BB isoenzyme (CK-BB) ELISA Kit

SL3353Hu 96 Tests
EUR 468

Anti- Creatine Kinase-BB Isoenzyme (CK-BB) Antibody

GWB-3EA958 1 mg Ask for price

Rat creatine kinase BB isoEnzyme, CK-BB GENLISA ELISA

KLR1929 1 x 96 wells
EUR 341

ELISA kit for Rat Creatine kinase BB isoenzyme (CK-BB)

KTE101077-48T 48T
EUR 424.8
Description: Quantitative sandwich ELISA for measuring Rat Creatine kinase BB isoenzyme (CK-BB) in samples from cell culture supernatants, serum, whole blood, plasma and other biological fluids.

ELISA kit for Rat Creatine kinase BB isoenzyme (CK-BB)

KTE101077-5platesof96wells 5 plates of 96 wells
EUR 2702.4
Description: Quantitative sandwich ELISA for measuring Rat Creatine kinase BB isoenzyme (CK-BB) in samples from cell culture supernatants, serum, whole blood, plasma and other biological fluids.

ELISA kit for Rat Creatine kinase BB isoenzyme (CK-BB)

KTE101077-96T 96T
EUR 686.4
Description: Quantitative sandwich ELISA for measuring Rat Creatine kinase BB isoenzyme (CK-BB) in samples from cell culture supernatants, serum, whole blood, plasma and other biological fluids.

Mouse creatine kinase BB isoEnzyme, CK-BB GENLISA ELISA

KLM1977 1 x 96 wells
EUR 341

ELISA kit for Human Creatine kinase BB isoenzyme (CK-BB)

KTE62696-48T 48T
EUR 398.4
Description: Quantitative sandwich ELISA for measuring Human Creatine kinase BB isoenzyme (CK-BB) in samples from cell culture supernatants, serum, whole blood, plasma and other biological fluids.

ELISA kit for Human Creatine kinase BB isoenzyme (CK-BB)

KTE62696-5platesof96wells 5 plates of 96 wells
EUR 2538
Description: Quantitative sandwich ELISA for measuring Human Creatine kinase BB isoenzyme (CK-BB) in samples from cell culture supernatants, serum, whole blood, plasma and other biological fluids.

ELISA kit for Human Creatine kinase BB isoenzyme (CK-BB)

KTE62696-96T 96T
EUR 646.8
Description: Quantitative sandwich ELISA for measuring Human Creatine kinase BB isoenzyme (CK-BB) in samples from cell culture supernatants, serum, whole blood, plasma and other biological fluids.

Recombinant Human Creatine Kinase BB (CK-BB) Isoenzyme

DAG279 1mg
EUR 1204.8

GWB-C3D70A-1MG - Creatine Kinase-BB Isoenzyme (CK-BB) Antibody

GWB-C3D70A-1MG 1mg
EUR 499

Rat Creatine Kinase BB Isoenzymes(CK-BB) ELISA Kit

NSL1053r 96 Tests
EUR 498

Human creatine kinase BB isoenzymes?CK-BB ELISA Kit

201-12-1253 96 tests
EUR 528
Description: A quantitative ELISA kit for measuring Human in samples from biological fluids.

Human creatine kinase BB isoenzymes(CK-BB)ELISA Kit

GA-E1269HM-48T 48T
EUR 346.8

Human creatine kinase BB isoenzymes(CK-BB)ELISA Kit

GA-E1269HM-96T 96T
EUR 559.2

Human creatine kinase BB isoenzymes(CK-BB)ELISA Kit

QY-E03022 96T
EUR 433.2

Human Creatine Kinase BB Isoenzymes(CK-BB) ELISA Kit

NSL0695Hu 96 wells
EUR 468

Human creatine kinase BB isoenzymes,CK-BB ELISA Kit

YLA0168HU-48T 48T Ask for price

Human creatine kinase BB isoenzymes,CK-BB ELISA Kit

YLA0168HU-96T 96T Ask for price

Bovine Creatine Kinase BB Isoenzymes(CK-BB) ELISA Kit

NSL1365Bo 96 T
EUR 528

Canine Creatine Kinase BB Isoenzymes(CK-BB)ELISA Kit

NSL1872Ca 1967 wells
EUR 528

Leave a Reply

Your email address will not be published. Required fields are marked *

Related Post

Completando la huella inmunológica mediante proteínas refractarias: Cribado de autoanticuerpos mediante una técnica mejorada de inmunotransferencia.Completando la huella inmunológica mediante proteínas refractarias: Cribado de autoanticuerpos mediante una técnica mejorada de inmunotransferencia.

La determinación de los autoantígenos de los autoanticuerpos serológicos requiere estrategias costosas, como los microarrays de proteínas o la IP+MS. Por lo tanto, los sueros suelen ser preseleccionados para detectar