Background
Biotin (also called vitamin H or vitamin B7) is a sulfur-rich water-soluble vitamin, abundant in tissues of animals and plants, as well as artificially made. It is necessary for natural growth, development, and normal body functions. Your hair, nails and skin, weight loss, pregnancy, and more all benefit from biotin. It's an experimental drug, clinically used for genetic disorders, multiple carboxylase deficiency, multiple sclerosis, hyperthyroidism and so on.
Biotin (coenzyme R since it is also a coenzyme of carboxylases) becomes active biotin when its carboxyl group is replaced with active groups. This functional biotin can also attach to macromolecules like antigens, antibodies and tracer enzymes. Avidin or anti-biotin is a large glycoprotein made up of four identical parts and the chemical in nature that binds to biotin most strongly. Biotin consists of an imidazolidone ring and a thiophene ring; the imidazolidone ring primarily binds with avidin, while the carboxyl group at the end of the thiophene ring side chain binds with antibodies and other macromolecules. One avidin molecule can bind to four biotin molecules. The binding between biotin and avidin is highly specific, stable, and has an extremely strong affinity, much stronger than that between antigens and antibodies. Streptavidin, secreted by Streptomyces, is a commonly used type of avidin in experiments due to its good stability, high yield, and ease of purification. It has been widely applied in the biotin-avidin (BAS) system.
Avidin is covalently bonded to biotin by a reaction between the tryptophan residues in avidin and biotin's imidazolidone ring 1:4. Their dissociation constant is 10-15 mol/L. Once liganded, the complex is highly stable and does not succumb to acids, bases, denaturers, heat, proteolytic enzymes or organic solvents. Biotin and avidin are both labelable with antibodies and other macromolecularly active materials, and with enzymes, fluorophores, radioactive isotopes and colloidal gold. So, the BAS is common in qualitative and quantitative trace antigen/antibody detection and localization methods. The main BAS methods are Bridge-Avidin-Biotin, Avidin-Biotin-Peroxidase Complex and Labeled Avidin-Biotin.
Figure 1. Sandwich assay with the use of fluorescent-tagged streptavidin detection
(Source: Mock DM. 2017)
Alternative Names
Vitamin H ELISA Kit
Vitamin B7 ELISA Kit
References
- 1. Mock DM. Biotin: From Nutrition to Therapeutics. J Nutr. 2017 Aug;147(8):1487-1492.
- 2. Dundas CM, et al. Streptavidin-biotin technology: improvements and innovations in chemical and biological applications. Appl Microbiol Biotechnol. 2013 Nov;97(21):9343-53.
References
Multiple Progressive Thermopreconditioning Improves Cardiac Ischemia/Reperfusion-induced Left Ventricular Contractile Dysfunction and Structural Abnormality in Rat
TRANSPLANTATION
Authors: Chen, Yueh-Hsi; Chiang, Chih-Yao; Chang, Tzu-Ching; Chien, Chiang-Ting
Abstract
Background. Triple progressive thermopreconditioning (3PTP) may induce high Hsp-70 expression to maintain cardiac function. We suggest that 3PTP may reduce myocardial ischemia/reperfusion (I/R) injury during organ transplantation through Bag3/Hsp-70 mediated defense mechanisms. Methods. Male Wistar rats were divided into sham control group and 72 h after 3PTP in a 42 degrees C water bath (3PTP) group. Rats underwent 60 min of ischemia by occlusion of the left anterior descending coronary artery followed by 240 min reperfusion. Hemodynamic parameters, including the electrocardiogram, microcirculation, heart rate, left ventricular end-diastolic pressure, maximal rate of rise (+dp/dt), and fall (-dp/dt) in the left ventricular pressure for index of contraction and relaxation were determined. Myocardial infarct size was evaluated by the Evans blue-2,3,5-triphenyltetrazolium chloride method. 3PTP-induced protective mechanisms were determined by Western blot and immunohistochemistry. Results. Cardiac I/R depressed cardiac microcirculation, induced S-T segment elevation, and R-R and P-R interval elongation increased infarct size associated with erythrocyte extravasation, leukocytes and macrophage/monocyte infiltration, granulocyte colony-stimulating factor, poly(ADP-ribose) polymerase 1 stain, and transferase-mediated dUTP-biotin nick end labeling positive cells. However, 3PTP evoked significant cardioprotection against I/R injury, characterized by the increased +dp/dt value and the decreased elevated left ventricular end-diastolic pressure, erythrocyte extravasation, leukocyte and macrophage/monocyte infiltration, granulocyte colony-stimulating factor expression, poly(ADP-ribose) polymerase 1 expression, transferase-mediated dUTP-biotin nick end labeling positive cells, and fragmentation and infarct area. In addition, 3PTP increased Hsp-70 and Bag3 expression and decreased Bax/Bcl-2 ratio, but did not affect the Beclin-1 and LC3-II/LC3-I ratio in the heart with I/R injury. Conclusions. 3PTP therapies may through Bag3 upregulation alleviate I/R injury-induced left ventricular structural deterioration and dysfunction.
Development of a novel polyprobe for simultaneous detection of six viruses infecting stone and pome fruits
3 BIOTECH
Authors: Noorani, Md Salik; Khan, Jawaid Ahmad
Abstract
A biotin-labeled, non-isotopic, novel polyprobe was developed for the simultaneous detection of six viruses viz. apple chlorotic leaf spot virus (ACLSV), apple mosaic virus (ApMV), apple stem grooving virus (ASGV), cherry virus A (CVA), prunus necrotic ringspot virus (PNRSV) and plum pox virus (PPV) infecting stone and pome fruit trees through dot-blot hybridization assay. The sensitivity of the polyprobe was checked by serial dilutions of total RNA extracted from the tissues of infected trees. ACLSV was detected up to a dilution of 5(-5), whereas ApMV, ASGV, CVA, PPV and PNRSV up to 5(-4). The developed assay was validated following testing a total of 45 symptomatic leaf samples collected from different geographical regions of Jammu and Kashmir (India), and the presence of the viruses was further confirmed by RT-PCR and sequencing. The polyprobe, designed for performing molecular hybridization assay can be developed quickly and avoid the tedious transformation and cloning procedures. Apart from simultaneously detecting viruses in stone and pome fruit trees, it holds great potential for virus indexing programmes to ascertain the supply of virus-free plant materials to the growers.
COA
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