Abdul Archive
Species of Pythium grow in water and soil as saprotrophs, but under suitable conditions, e.g. where seedlings are grown crowded together in poorly drained soil, they can become parasitic, causing diseases such as pre-emergence killing, damping off and foot rot. …
Fundamental concepts and definition: Plasmids are autonomous extrachromosomal replicons found commonly in prokaryotes, but also in eukaryotes and their organelles. They are generally covalently closed and superfoiled circles of double-stranded DNA with sizes ranging from 1 to 300 kbp. They …
RNA molecules with catalytic ability are known as ribozymes . Some ribozymes act by cleaving other RNA molecules. Such ribozymes have catalytic domains that carry out the reaction fused to domains that recognize the substrate RNA by base pairing. If …
Although most cancers are not inherited via the germ line, cancer is nonetheless a genetic disease. In the case of hereditary disease we may attempt to replace the defective component, thus preventing cell death. In contrast, when dealing with a …
About 10% of gene therapy trials have used liposomes . These are hollow microscopic spheres of phospholipid, and can be filled with DNA or other molecules during assembly. The liposomes will merge with the membranes surrounding most animal cells and …
Severe combined immunodeficiency (SCID) occurs when both the B cells and T cells of the immune system are defective and results in an almost totally defective immune response. Children with SCID have to be shielded from all contact with other …
Retroviruses infect many types of cells in mammals. They need dividing cells for successful infection, and will not infect many tissues where host cell growth and division have come to a standstill. Moreover, the genetic material of retroviruses passes through …
About one in 2000 white children suffer from cystic fibrosis . This condition is due to homozygous recessive mutations. In other words two defective copies of the gene, one from each parent, must be inherited for the child to suffer …
Adenoviruses are relatively simple, double-stranded DNA viruses that infect humans and other vertebrates. The virus particle consists of a simple icosahedral shell, or capsid, containing a single linear dsDNA molecule of approximately 36,000 base pairs. A terminal protein protects each end …
The original idea behind gene therapy was curing hereditary defects by replacing defective genes. However, there is no inherent reason why gene therapy must only be “defensive” and suppress defects. We can go on the offensive and provide genes whose …