science world

                                                                                     BACTERIAL TOXINS Toxin are major determinants of virulence There are two two type toxin such as 1.     Endotoxins [secreted by Gram negative bacteria (Lipid A)] 2.     Exotoxin   Endotoxins: - This are the cell wall component of Gram-negative bacteria, which generally involved in pyrogen also in inflammation.   Exotoxin: - This are the protein glycoprotein which are secreted by bacteria which are generally enzymes and alter host metabolism e.g. Diphtheria toxins, cholera toxins, tetanus toxins. Cholera toxin: - -    ...

                                 RFLP (Restriction Fragment Length Polymerization)     Principle: - Restriction fragment length polymerization (RFLP) technique in which organism may be differentiated by analysis of pattern derived from cleavages of this DNA -         If two organism differ in this distance between sites of cleavage of particular restriction endonucleases, the length of the fragment produced wise differ when the DNA is digested with a restriction enzyme. -         The similarity of the pattern generated can be used to differentiated species (and even strain) from one other.   Introduction: - Alc Jeffery in 1985 discovered the technique called restriction fragment length polymerization (RFLP) -         RFLP is t...

Classical complement pathway: -         after entry of antigen in the blood IgM and IgG type of antibody bind to its surface, other type of antibody’s [ IgD, IgE, IgA ] can not activate. -         Ones IgG and IgM antibody bind to surface of antigen conformation changes occur in Fc region of antibody bn Fc region of antibody due to this conformation changes -         A pocket is created for the binding of complement protein known as clqr2s2 after binding to Fc region of antibody clqr2s2 get activated and it gets photolytic activity clqr2s2   bar has to substrate -         C2 protein and C4 protein it clues C4 into C4a and C4b in which C4b is longer factor and C4a is smaller than smaller fragment dissociated and the larger fragment C4b bind to the surface of antigen it clues C2 into C2a and C2b in which C2a is longer fragment and C2b is ...

Designing probe: - 1.      A probe is a nucleic acid molecule (single stranded DNA or RNA) with a strong affinity with a specific target 2.      Probe and target base sequence must be compliment to each other beet depending on the conditions the do not necessarily have to be complementary. 3.      Probe design depends upon whether a gene probe an oligonucleotide probe is desired. Gene Probe: - Gene probe are generally longer than 500 bp and comprise all or most of the target gene. They can be generated in two ways. Clone Gene Probe: - -         Clone probe are generally used when clone species is available or when DNA sequence is unknown must be done first in order to be map and sequence. -         It is usual to cut the gene with restriction enzyme and excise it from and agarose gel, although if the vector has no this might no...

Yeast two hybrid assay: -                                          Study interaction, detecting protein-protein interaction.   Principle of the two-hybrid: - A] Standard model of transcription activator: -     - The DNA binding domain of an activator binds to an enhancer.     - The activating domain interacted with the based complex. Recruiting it the promoter       B] Two hybrid assay for protein-protein interaction using gene clone technique linked the gene one protein to the part of a gene encoding a DNA binding domain, to encode 1 hybrid protein, linked the gene for another protein to the part of the gene encoding a transcription activating domain to encode a two hybrid proteins are introduce into yeast...