The selection and hypermutation of the B cell antigen receptor (BCR) takes place in germinal center (GCs). The presence of antigen triggers the B cell differentiation. The development of B cell includes its maturation, activation and differentiation into B plasma cells and B memory cells. The lymphoid progenitor in the bone marrow is differentiated into pro B cell. This pro B cells then undergoes a series of differentiation which includes pre B cells then immature B cells and finally mature B...
Alternative σ-factors of bacteria bind core RNA polymerase to program the specific promoter selectivity of the holoenzyme. Signal-responsive changes in the availability of different σ-factors redistribute the RNA polymerase amongst the distinct promoter classes in the genome for appropriate adaptive, developmental and survival responses. The σ54-factor is structurally and functionally distinct from all other σ-factors. Consequently, binding of σ54 to RNA polymerase confers unique features...
Green revolution technologies arrived in Pakistan in the 1960's through the introduction of high yielding varieties (HYV's). After about 4-5 years this technology proved ineffective because those HYV's need irrigated conditions, costly chemical fertilizers, pesticides and insecticides. Frequent irrigation caused severe damage to soil conditions in the form of salinity over a wide area and cause significant genetic erosion (Yasin, 2007). Field concentrations of fungicides have induced negative...
Superconductivity is a phenomenon that occurring in certain materials such as metal and alloys and characterized by the absence of the complete electrical resistivity and interior magnetic field damping. Superconductivity occurs in a large amount of materials, including simple elements like tin and aluminium, various metallic alloys, some heavily-doped semiconductors, and certain ceramic compounds containing copper and oxygen atoms lanes. Superconductivity does not occur in noble metals like...
The study of drug-human serum albumin binding affinity is considered as an important topic in the drug discovery and development. Capillary electrophoresis based on the principles of frontal analysis (CE-FA) is one of the most important technique, due to the short analysis time, high separation efficiency, low sample requirement, easy computerization, robustness, precision of results, low cost sample throughput and versatility to study multiple equilibria. This method is used to study the...
Dr. Warren Tay (1843-1927) and Dr. Bernard Sachs (1858-1944) were the two men for which Tay-Sachs disease was named. (U.S. National Library of Medicine 2010). In 1881, Dr. Warren Tay was an ophthalmologist from Britain who first identified a patient with a cherry-red spot on the retina of their eye (Mayo Clinic 2010). A neurologist from New York, Bernard Sachs, worked a few years later and gave the first report on the cellular basis of Tay-Sachs disease. Sachs also realized that the...
BIO450 Primer Design Tutorial The most critical step in your PCR experiment will be designing your oligonucleotide primers. Poor primers could result in little or even no PCR product. Alternatively, they could amplify many unwanted DNA fragments. Either way, it would interfere in subsequence cloning steps. Therefore it is critical that you design your primers carefully. Primer design requires extensive computer-based sequence analysis and this tutorial is designed to lead you through that...
This experiment was designated to investigate the effect of temperature on metabolic rate of lucilia sericata larvae. Water bath has been used to set up the different temperatures of water at 300C, 350C, 400C, 450C, 500C and 550C. lucilia sericata larvae were chosen to show the effect of different temperature on biological reaction of organism. The active lucilia sericata larvae of the same size were soaked in different temperature of water for about 30 seconds and the number of wriggles was...
Many distinctive properties of Green Fluorescent Protein (GFP) such as its ability to generate an internal fluorophore make it extra-ordinary. This review will set out to discuss not only the structural and biochemical properties, uses and interesting features of this unique protein but also the applications of new variants of GFP that have been developed. INTRODUCTION GFP comprises of 238 amino acids, absorbs blue light (Amax 395 nm) to fluoresce green light (Imax 509 nm) (Miller et al, 2008)....
Cotton is the most important cash crop of Pakistan known as "white gold" (Ahmad, 2007). Pakistan is the fourth largest producer of cotton in the world, third largest exporter of raw cotton, fourth largest consumer of cotton, and the largest exporter of cotton yarn. 1.3 million farmers (out of a total of 5 million) cultivate cotton over 3 million hectares, covering 15 per cent of the cultivable area in the country (Abro et al., 2004). Economy of Pakistan is heavily dependent on the...