[Certification of a kit for immunologic tests].

T A Bektimirov; V F Petrov; P Miete; T S Shobukhova; A M Nikolaeva; G M Tumanova; U Erkhardt; K Erkhardt

PubMed · 9662796

[Certification of a kit for immunologic tests].

T A Bektimirov·V F Petrov·P Miete·T S Shobukhova·A M Nikolaeva·G M Tumanova·U Erkhardt·K Erkhardt

Abstract

A diagnostic kit for the determination of IgG antibodies to diphtheria toxin ("Abion", Germany) the use of analytical columns "Abicap" was studied in the specialized laboratory of the Tarasevich State Control Institute with a view to determine the possibility of its official registration in the Russian Federation. The kit was evaluated by the following criteria: the correspondence of the specified properties of the preparation to those actually observed; meeting the norms stated in the documents supplied with the kit and WHO requirements; the presence of advantages in comparison with the enzyme immunoassay. In the course of the trial positive results were obtained on all these points.

Explore related subjects

Diphtheria Toxin Humans Immunoenzyme Techniques Immunoglobulin G Reagent Kits, Diagnostic Reference Standards Reproducibility of Results Russia Serologic Tests Statistics as Topic World Health Organization English Abstract Journal Article

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

T A Bektimirov, V F Petrov, P Miete, T S Shobukhova, A M Nikolaeva, G M Tumanova, U Erkhardt, K Erkhardt. [Certification of a kit for immunologic tests].. https://pubmed.ncbi.nlm.nih.gov/9662796/

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2006

Chaperoning of insertion of membrane proteins into lipid bilayers by hemifluorinated surfactants: application to diphtheria toxin.

Hemifluorinated compounds, such as HF-TAC, make up a novel class of nondetergent surfactants designed to keep membrane proteins soluble under nondissociating conditions [Breyton, C., et al. (2004) FEBS Lett. 564, 312]. Because fluorinated and hydrogenated chains do not mix well, supramicellar concentrations of these surfactants can coexist with intact lipid vesicles. To test the ability of HF-TAC to assist proper membrane insertion of proteins, we examined its effect on the pH-triggered insertion of the diphtheria toxin T-domain. The function of the T-domain is to translocate the catalytic domain across the lipid bilayer in response to acidification of the endosome. This translocation is accompanied by the formation of a pore, which we used as a measure of activity in a vesicle leakage assay. We have also used Förster resonance energy transfer to follow the effect of HF-TAC on aggregation of aqueous and membrane-bound T-domain. Our data indicate that the pore-forming activity of the T-domain is affected by the dynamic interplay of two principal processes: productive pH-triggered membrane insertion and nonproductive aggregation of the aqueous T-domain at low pH. The presence of HF-TAC in the buffer is demonstrated to suppress aggregation in solution and ensure correct insertion and folding of the T-domain into the lipid vesicles, without solubilizing the latter. Thus, hemifluorinated surfactants stabilize the low-pH conformation of the T-domain as a water-soluble monomer while acting as low-molecular weight chaperones for its insertion into preformed lipid bilayers.

Diphtheria Toxin↗

PubMed2004

Reversible refolding of the diphtheria toxin T-domain on lipid membranes.

The catalytic domain of diphtheria toxin (DT) is translocated across endosomal membranes by the T-domain (DTT) in response to acidification. Understanding the energetics of translocation, besides clarifying the mechanism of translocation, should provide insights into general principles of membrane protein stability and assembly. As a first step, we have evaluated the energetics of DTT binding to lipid vesicles using three single-cysteine mutants (L350C, Q369C, and Y280C) labeled with a 7-nitrobenz-2-oxa-1,3-diazol-4-yl (NBD) fluorophore sensitive to polarity changes. Remarkably strong association with the vesicles was detected for all mutants, even at pH 7 at which DTT is believed to be in a fully folded membrane-incompetent state. Lowering the pH in the presence of anionic membranes resulted in a strong but reversible increase in emission of NBD-labeled mutants, consistent with reversible membrane insertion. This reversibility permitted free energies of DTT interactions with vesicles to be determined for the first time. Free energy values for the three mutants ranged from -8 to -10 kcal mol(-1) at pH 4.3 and from -7 to -8 kcal mol(-1) at pH 7. Insights into the disposition of DTT on membranes were obtained using a novel hydropathy analysis that considers the relative free energies of transmembrane and interfacial interactions as a function of pH. This analysis suggests that interactions at the membrane interface dominate pH-triggered insertion of DTT, implying that the folding pathway involves interfacial intermediates.

Diphtheria Toxin↗

PubMed2004

A large-scale Agrobacterium-mediated transformation procedure with a strong positive-negative selection for gene targeting in rice (Oryza sativa L.).

A large-scale transformation procedure handling an adequate number of stable transformants with highly efficient positive-negative selection is a necessary prerequisite to successful gene targeting by homologous recombination, as the integration of a transgene by somatic homologous recombination in higher plants has been reported to be 10(-3) to 10(-5) compared with random integration by non-homologous end joining. We established an efficient and large-scale Agrobacterium-mediated rice transformation protocol that generated around 10(3) stable transformants routinely from 150 seeds and a strong positive-negative selection procedure that resulted in survivors at 10(-2) using the gene for diphtheria toxin A fragment as a negative marker. The established transformation procedure provides a basis for efficient gene targeting in rice.

Diphtheria Toxin↗