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Home >> Dictionary of Bioinformatics, Biochemistry, Biotechnology >> Bacillus Calmette-Guerin (BCG)

B cells A major class of white blood cells that differentiate in the bone marrow to produce antibody-forming cells and memory cells. They are responsible for the antibody mediated or humoral immune response. See B lymphocytes.

B-DNA A right handed duplex DNA structure containing 10.5 base pairs per turn of the helix. B-DNA is the most common form of DNA found in nature. See DNA


B-DNA


B DNA

B lymphocytes An important class of lymphocytes that undergo differentiation in the bone marrow (in mammals) and the Bursa of Fabricius (in birds). These cells are responsible for antibody – mediated or humoral immune response. They give rise to the antibody – forming plasma cells and memory cells of the immune system.

Bacillus Calmette–Guerin (BCG) A nonvirulent form  of Mycobacterium bovis that causes tuberculosis in cows. It was isolated By Calmette and Guerin and used as a vaccine against tuberculosis since 1928.

Bacillus subtilis A bacterium commonly used as a host in recombinant DNA experiments because of its ability to secrete proteins.

Bacillus thuringiensis (B.t) Naturally occurring soil bacterium that generates a crystalline protein, a product of the cry gene that is toxic to a variety of Lepidoptera but is harmless to animals and humans. Transgenic plants expressing the δ-endotoxin of Bacillus thuringiensis (B.t) have been created. The endotoxin gene is cloned into vectors and transferred into crop plants.

This enables the plants to produce the endotoxin in their tissues and kill insect pests. The endotoxins present in the inactive form are activated in the insect midgut. The active toxin binds to the receptors on the surface of the midgut causing ionic imbalance, cell burst, lysis and eventually death of the insect.

Bacitracin An antibiotic effective against Gram-positive bacteria that inhibits cell wall synthesis.

Backbone 1. In a vertebrate, refers to the spinal column. 2. A structural feature of  a molecule arising from the primary structure. A protein backbone is formed by linking joining of nucleotide residues by phosphodiester bonds.

Backcross Crossing an organism with one of its parents or with a genetically equivalent organism. The offspring are termed as the backcross generation of backcross progeny.

Backmutation A second mutation that occurs at the same site in a gene as the original mutation. It reverses the effect of an inactivating gene mutation. The second mutation restores the wild - type nucleotides sequence.

Back – propagation An algorithm used to modify network weights when training feed- forward neural networks. After each training, input pattern is fed through the network, the networks output is compared with the desired output and the amount of error is calculated. The error is back-propagated through the network using an error function to correct the network weights.

B-series N-terminal fragments in a peptide ladder produced by mass spectrometry.

B1 element  A class of dispersed repetitive elements found in mice. These are categorized as short interspersed nuclear elements(SINES)

B7 A membrane co – stimulatory molecule that activates B cells and macrophages.

Bacillus A rod –shaped bacterium

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