Humulin: The synthetic insulin

Diabetes has been a problem in society for a long time and for decades the peoples suffering from this disease had to depend on the insulin isolated from the pancreas of the slaughtered calves. The problem in using this insulin was that it was not exactly similar to that of human insulin and due to this reason it caused allergic reactions in large number of the population using it. As a solution to this problem, human insulin was prepared synthetically using the techniques of genetic engineering.

The human insulin consists of two chains of polypeptide, chain A with 21 amino acids residue and chain B with 30 amino acids residue and both the chains are joined together with disulfide bonds. These chains are synthesized in the β cells of the islets of Langerhans present in the pancreas. In order to synthesize the human insulin artificially, the genes responsible for synthesis of both the polypeptide chains were isolated from the pancreas of a human and was then replicated and inserted in E.coli. The transformed bacteria were then selected and cloned multiple times to form a colony.

The transformed colonies synthesized the chains of amino acids separately which were then joined artificially to form the disulfide bonds which rendered fully functional insulin. This insulin has all the properties of human insulin and does not cause any allergic reactions. It is also readily absorbed in the body when compared to the animal insulin.


Artificial mutation transferred to the progeny

A few months back researchers successfully developed a genetically altered organism capable of transferring its altered gene to its progeny. It is a major breakthrough in the field of genetics and a major milestone for the researchers working towards the development of designer organisms.

Under normal circumstances there is only 50 percent chance of a particular gene being passed to progeny from its parent as each parent contribute only half of the genome. But in a recent development the biologists from the University of California, San Diego, found a novel technique to ensure that an offspring of fruit fly (Drosophila melanogaster) received a particular gene from a parent for up to 95 percent of time. Their research has been published in Science.

The researchers used CRISPR technique of genetic engineering to make sure that the mutation introduced in one chromosome of the genome of the fruit fly automatically transfers to the homologous chromosome as stated by Valentino Gantz, a co-author of the study. Since the mutation is introduced in both the chromosomes of the genome, it is always transferred to the progeny no matter which set is being transferred. The researchers have named this process as “Mutagenic Chain Reaction” (MCR).

This technique of MCR has capability of transforming a population of sexually reproducing organisms in a very short span of time. This technique has a potential of developing the pests or mosquitoes that are not capable of spreading the diseases.

Bt Technology

Bt stands for Bacillus thuringiensis. It is a bacterium which produces over 200 toxins, which are harmful to different insect species. Bt toxins are insecticidal to different larvae of beetles, butterflies and flies but are harmless to other life forms. The Bt toxin gene have been successfully inserted into the different variety of crops such as cotton, brinjal etc. to protect them from various insects which lead to mass destruction of crops and great loss to human income.

The Bt gene is isolated from the bacterium and is inserted in the crops which lead to the production of the cry protein, which is an endotoxin. When insects eat the plant, this cry protein gets dissolved due to high pH level of insect’s gut. These cry protein attach to the specific cadherin protein present inside the epithelial cell of insect which leads to unregulated flow of potassium ions inside the cell, which in turn leads to the death of the cells and ultimately death of insect.

However, it is completely safe for human consumption as in the human gut; it encounters the acidic environment due to which it cannot be activated. Bt technology is considered to be the friendly measure for farmers as it save a huge amount of money that is going to be spent on chemical insecticide.

But use of Bt crops is not approved in many parts of the world due to the integration of a foreign gene. Also there is a threat of contamination by the foreign gene in the genome of the plants of wild species.

Protein Folding Mechanism Unveiled

In a recent research study, scientists have successfully discovered a mechanism involved in protein folding. Although protein synthesis was understood a long time ago, the mechanism involved in the folding of protein was not understood fully.

In a study published in the “Nature Chemical Biology”, scientists mentioned that if the whole process of the protein synthesis goes on as planned, the amino acids get aligned in an orderly manner and the folding occurs within a fraction of a second.

Any anomaly during the protein folding results in the clumping of the proteins together, and can result in many serious diseases such as cystic fibrosis and Parkinson’s disease. Due to this, a proper understanding of the folding mechanism can result in an early detection and treatment of such diseases at a very early stage.

The researchers focused their study on the membrane proteins that perform various vital functions such as transport across the membrane, maintenance of the resting membrane potential, cellular excretion, etc. The researchers used a novel technique called “steric trapping” to study the mechanism of folding. This technique involves attachment of two molecular tags to the folded protein then, few bulky objects capable of attaching with the tags are added. These bulky objects bring back the protein back to the unfolded state which can then be studied to determine the role of amino acids in folding the protein.