DIARECT Newsletter

Dear Madam or Sir,

Expecting a record attendance of 19,000 this year, the annual meeting of the American Association for Clinical Chemistry is one of the world's largest medical shows. Together with the Clinical Lab Expo AACC’s Annual Meeting is held July 15-19, 2012 and brings presenters and exhibitors from all over the world to the Los Angeles Convention Center.

If you like to speak with a member of the DIARECT team, please contact us at:
Tel.       +49 761 47979-0
Email   info@diarect.com

Also, please feel free to stop by booth #2246 of our partner company SurModics IVD.

This newsletter is dedicated to the introduction of our newest products, a non recombinant, bovine DNA-Topoisomerase I (Scl-70) antigen and BioFX® TMB Extended Range HRP Microwell Substrate.

For more information on our products, autoimmune antigens and antigens for infectious diseases, as well as our SurModics protein stabilization products BioFX substrates,
and accessory reagents please visit our website at www.diarect.com.

Pleasant reading!

The DIARECT team

Non recombinant, bovine DNA Topoisomerase I (Scl-70) now available!

DNA toposisomerase I (EC is a key nuclear enzyme that interconverts supercoiled DNA to the required topological conformations for normal DNA replication and transcription. This enzyme is the target antigen for the so-called Scl-70 autoantibodies, which in turn are a highly specific marker in scleroderma patients (specificity 98-100%). Scleroderma is a rare connective tissue disorder characterized by abnormal thickening of the skin. A number of different autoantibodies are known to occur in scleroderma patients. The presence  of Scl-70 autoantibodies is very often associated with diffuse skin involvement and pulmonary fibrosis.  

In human tissues DNA topoisomerase I is initially synthesized as a protein with a molecular weight of 100 kDa. Most of this precursor is then proteolytically processed to a 70-kDa size, from which the Scl-70 antigen has derived its name.

DIARECT’s well known recombinant DNA topoisomerase I (Scl-70) antigens are expressed in and purified from the baculovirus / insect cell expression system. To allow optimal assay development DIARECT offers two distinct Scl-70 antigens: one is the full-length 100-kDa enzyme precursor, the other one is a truncated form resembling the processed 70-kDa form of the antigen.  

Now, also a native DNA topoisomerase antigen is available, being characterized by the same high quality and lot-to-lot consistency as the recombinant targets. Research data strongly suggest that the native antigen as well as the recombinant targets perform equally well in dot blot analyses (for representative data please see the figure below). Native DNA topoisomerase is purified from bovine calf thymus.

With the non recombinant, bovine Scl-70 DIARECT now offers the complete range of DNA topoisomerase I antigens to cover all your needs.

Figure:  Dot blot analyses of sera from blood donors (1-5) and patients with presumed systemic sclerosis (6-12). Recombinant proteins Scl-70 (full length, lot 24B04) and Scl-70 (truncated, lot 45702) were analyzed and compared to Scl-70 antigen (non recombinant) purified from bovine sources (lots 15D01, 15D02 and 15D03).

Ordering information:


BioFX TMB Extended Range HRP Microwell Substrate

Substrate choice is a critical consideration during assay development and can impact factors such as sensitivity, dynamic range and reproducibility. BioFX® TMB Extended Range HRP Microwell Substrate (TMBX) is the most recent addition to SurModics’ family of TMB HRP substrates.

Use of TMBX in a quantitative assay (i) can increase the assays upper limit of quantitation and (ii) maintain the detection limits and analytical sensitivity achieved with other substrates in our TMB family.
Use of TMBX also improves the reproducibility of the assay through lower backgrounds and control of assay timing.


Figure: Standard curve comparison for TMBW and TMBX stopped and read at 450 nm using a model assay system. Rabbit Rabbit anti-mouse IgG was coated on a ELISA plate and stabilized with StabilCoat® Immunoassay Stabilizer. Biotinylated mouse IgG was titrated in StabilZyme® Select Conjugate Stabilizer and incubated for two hours at room temperature. After washing diluted Streptavidin-peroxidase was added and incubated for 20 minutes at room temperature. After a final wash the substrate was added and developed. Results show an extended dynamic range when TMBX is used.

SurModics' choice of substrates with varying detection levels:

For additional product information and/or evaluation samples please get in touch with us:
Tel.       +49 761 47979-0
Email   info@diarect.com


Upcoming Events - meet the DIARECT team!

AACC and Clinical Lab Expo
Date: July 15 -19, 2012
Location: Los Angeles, CA
AMLI 25th Annual Meeting
Date: August 4 -7, 2012
Location: Minneapolis, MN


Distributor - North America

SurModics IVD

9924 West 74th Street
Eden Prairie, MN 55344  USA

Phone: +1 952 500 7200
Toll-free: +1 800 755 7793
Fax: +1 952 500 7201



Distributors - China
Biobridge Logo

Beijing Biobridge Bio-technology Inc.

Room 221, Fanghezhengyuan B Building
Guanghua Road 16
Tongzhou Industry Development District
Beijing 101113
P.R. China

Phone: +86 10 61507875
Fax: +86 10 61507837 808
Email: order@bjbiobridge.com.cn


BioSun Logo

Shanghai BioSun Sci&Tech Co., Ltd.

Room E2, 6F, Bldg. No.1
825 Zhaojiabang Road
Shanghai 200032
P.R. China

Phone: +86 21 54253791
Fax: +86 21 64280007
Email: biosun@biosun.cn




If you would like to receive more detailed information on DIARECT products, please follow this link to our contact and order form.

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