BIOTECHNOLOGY TOPICS FOR UPSC | CURRENT AFFAIRS

STEM CELL

• Stem cells are the body’s raw materials — cells from which all other cells with specialized functions are generated.
• Under certain conditions in the body or a laboratory, stem cells divide to form more cells called daughter cells.
• These daughter cells either become new stem cells (self-renewal) or become specialized cells (differentiation) with a more specific function, such as blood cells, brain cells, heart muscle cells or bone cells.
• No other cell in the body has the natural ability to generate new cell types.

Types of cells

Stem cells are of the following different types:

• Embryonic Stem Cells
• Adult Stem Cells
• Induced Pluripotent Stem Cells
• Mesenchymal stem cells

Embryonic Stem Cells

The fertilized egg begins to divide immediately. All the cells in the young embryo are totipotent cells. These cells form a hollow structure within a few days. Cells in one region group together to form the inner cell mass. This contains pluripotent cells that make up the developing foetus.

The embryonic stem cells can be further classified as:

• Totipotent Stem Cells: These can differentiate into all possible types of stem cells.
• Pluripotent Stem Cells: These are the cells from early embryo and can differentiate into any cell type.
• Multipotent Stem Cells: These differentiate into a closely related cell type. For eg., the hematopoietic stem cells differentiate into red blood cells and white blood cells.
• Oligopotent Stem Cells: Adult lymphoid or myeloid cells are oligopotent. They can differentiate into a few different types of cells.
• Unipotent Stem Cells: They can produce cells only of their own type. Since they have the ability to renew themselves, they are known as unipotent stem cells. For eg., Muscle stem cells.

Adult Stem Cells

These stem cells are obtained from developed organs and tissues. They can repair and replace the damaged tissues in the region where they are located. For eg., hematopoietic stem cells are found in the bone marrow. These stem cells are used in bone marrow transplants to treat specific types of cancers.

Induced Pluripotent Stem Cells

These cells have been tested and arranged by converting tissue-specific cells into embryonic cells in the lab. These cells are accepted as an important tool to learn about normal development, onset and progression of the disease and also helpful in testing various drugs. These stem cells share the same characteristics as embryonic cells do. They also have the potential to give rise to all the different types of cells in the human body.

Mesenchymal Stem Cells

These cells are mainly formed from the connective tissues surrounding other tissues and organs known as stroma. These mesenchymal stem cells are accurately called stromal cells. The first mesenchymal stem cells were found in the bone marrow that are capable of developing bones, fat cells, and cartilage.

There are different mesenchymal stem cells that are used to treat various diseases as they have been developed from different tissues of the human body. The characteristics of mesenchymal stem cells depend on the organ from where they originate.

What is stem cell therapy?

• Stem cell therapy, also known as regenerative medicine, promotes the repair response of diseased, dysfunctional or injured tissue using stem cells or their derivatives.
• Stem cells can then be implanted into a person. For example Mumbai baby boy was injected with 40 million stem cells and gradually the lungs began to repair. In this case, doctors used mesenchymal stem-cell therapy (these are adult stem cells and are different from Embryonic stem cells) on an experimental basis

Why it is an issue?

• In March 2019, the Union Health Ministry had notified the ‘New Drugs and Clinical Trial Rules, 2019’ which state that stem-cell derived products are to be used as “new drugs”. “This means that any doctor who uses stem-cell therapy needs to take permission from the government.

Advantages of Stem cell Therapy:

• Immense Medical Benefits: It offers a lot of medical benefits in the therapeutic cloning and regenerative medicine
• Treatment of Conditions and Disorders: It shows great potential in the treatment of a number of conditions like Parkinson’s disease, spinal cord injuries, Alzheimer’s disease, schizophrenia, cancer, diabetes and many others.
• A Better Knowledge of human growth: It helps the researchers know more about the growth of human cells and their development.
• The stem cell research can allow the scientists to test a number of potential medicines and drugs without carrying out any test on animals and humans. The drug can be tested on a population of cells directly.
• Cure development defects before they happen: The stem cell therapy also allows researchers to study the developmental stages that cannot be known directly through the human embryo and can be used in the treatment of a number of birth defects, infertility problems and also pregnancy loss. A higher understanding will allow the treatment of the abnormal development in the human body.
• Reduced risk of rejection: The stem cell therapy puts into use the cells of the patient’s own body and hence the risk of rejection can be reduced because the cells belong to the same human body.

Challenges in SCT

• Destruction of blastocysts: The use of the stem cells for research involves the destruction of the blastocysts that are formed from the laboratory fertilization of the human egg.
• Unknown side-effects: Like any other new technology, it is completely unknown what the long-term effects of such an interference with nature could be
• Limitations of adult cells: The disadvantage of adult stem cells is that the cells of a particular origin would generate cells only of that type, like brain cells would generate only brain cells and so on.
• Potential Rejection: If the cells used in the therapy are embryonic, then the cells will not be from the same human body and there are chances of rejection.
• Potential use in negative activities: It can be used to create bio-weapons or weapons of mass destruction

Applications of SCT

• Orthopedic injuries and musculoskeletal problems
• Wounds and incisions following surgeries
• Spinal cord injuries, brain trauma and spinal stenosis
• Cardiovascular diseases, including hypertension, coronary heart disease, stroke and congestive heart failure
• Hair loss
• Vision impairment
• Diabetes and other pancreatic dysfunctions
• Neurodegenerative diseases such as Parkinson’s, multiple sclerosis and Alzheimer’s

India and Stem Cell Therapy

• According to the Indian Council of Medical research, all stem cell therapy in India considered to be experimental except bone marrow transplants
• Stem cell therapy is legalized in India
• Umbilical cord and adult stem cell treatment are considered permissible
• Embryonic stem cell therapy and research is restricted

CHINA’S GENE EDITING RULES

China has decided to introduce new Gene-editing rules.

• Rules require researchers to obtain prior approval from the government before undertaking clinical trials.
• Those found violating the rules will be punished and this includes a lifetime ban on research.
• The rules would also require all future trials to be approved by administrative authorities as well as ethical committees.

Background

• Last year, a chinese researcher, He Jiankui, has claimed that he used CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) to produce the world’s first gene-edited babies to make babies immune to infection by the human immunodeficiency virus (HIV).
• After the news of gene-edited babies came Chinese national health commission investigated and found that Dr. He had violated the national regulations against using gene-editing for reproductive purposes.
• China has now decided to come up with stricter norms regarding gene editing.

Gene Editing

• Gene editing is also called as genetic modification, genetic manipulation or genetic engineering.
• Genome editing is a group of technologies that give scientists the ability to change an organism’s DNA (Deoxyribonucleic acid). These technologies allow genetic material to be added, removed, or altered at particular locations in the genome.
• Gene Editing is widely practised in agriculture, to increase productivity or resistance to diseases, etc.

What is CRISPR?

• Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) is a gene editing technology, which replicates natural defence mechanism in bacteria to fight virus attacks, using a special protein called Cas9.
• CRISPR-Cas9 technology behaves like a cut-and-paste mechanism on DNA strands that contain genetic information. The specific location of the genetic codes that need to be changed, or edited, is identified on the DNA strand, and then, using the Cas9 protein, which acts like a pair of scissors, that location is cut off from the strand.
• A DNA strand, when broken, has a natural tendency to repair itself. Scientists intervene during this auto-repair process, supplying the desired sequence of genetic codes that binds itself with the broken DNA strand.
• CRISPR-Cas9 is a simple, effective, and incredibly precise technology with potential to revolutionise human existence in future.

Issues

• Dr. He used the CRISPR–Cas9 gene editing technique to disable a gene called CCR5 (C-C chemokine receptor type 5), which encodes a protein that allows HIV to enter and infect cells.
• Though no guidelines have been drawn up so far regarding gene editing.
• There is a general consensus in the scientific and ethics communities that the CRISPR–Cas9 gene-editing technique should not be used clinically in embryos..
• Importantly, human clinical trials have not been carried out anywhere in the world to test whether disabling the gene completely prevents HIV infection.
• In the absence of any clinical trial data as well as consensus to use this tool to prevent HIV infection, performing it on babies as a form of medical intervention is unethical.

CCR5

• C-C chemokine receptor type 5, also known as CCR5 or CD195, is a protein on the surface of white blood cells that is involved in the immune system as it acts as a receptor for chemokines.
• CCR5, which encodes a protein that allows HIV to enter and infect cells. The CCR5 gene protective role against the West Nile virus is well established.
• The CCR5 gene also helps to protect the lungs, the liver and the brain during certain serious infections and chronic diseases.
• The gene is known to prompt the immune system to fight the influenza virus in the lungs.

RNA INTERFERENCE (RNAi)

RNAi is a gene silencing technology that inhibits protein synthesis in target cells using double-stranded RNA. Same result is achieved by Antisense technology through single-stranded RNA.

• RNAi technologies are now known to formulate drugs capable of reducing cholesterol levels by half. The technology also finds immense importance in treating acute viral infections like acquired immunodeficiency syndrome (AIDS), because of the well-studied life cycle and pattern of gene expression of the human immunodeficiency virus (HIV).
• Promising results have been shown by Antisense technology in producing a variety of tomato with increased shelf-life commonly known as Flavr Savr.
• It can be said that, in the near future, antisense technology could be used in targeting cancer.

Constraints hampering the growth of these technologies in India:

• Very few companies working with these technologies in India.
• Poor translation of this nucleic-acid based therapy to clinical studies.
• Lack of efficient and targeted delivery vehicles for these potential RNA molecules. Though this is one of the objectives of a stand-alone programme on nano-biotechnology under department of biotechnology, research gaps continue to exist.
• The relatively minimal development of silencing reagents that ensure significant, specific, consistent and lasting knockdown of the target gene.

Extras:

Gene Silencing Technique

• Gene silencing is a technique that aims to reduce or eliminate the production of a protein from its corresponding gene.
• It generally describe the “switching off” of a gene by a mechanism other than genetic modification
• It occurs when RNA is unable to make a protein during translation (gene expression).
• In the groundnut case, the researchers designed two small RNA molecules that silence the fungal genes which produce aflatoxin.
• When the fungus and plant come in contact with each other the small RNA molecules from the plant enter the fungus and prevent it from producing aflatoxin (protein) by its corresponding gene.

GENETICALLY MODIFIED AEDES AEGYPTI

What is the initiative?

• Aedes aegypti mosquito is the carrier of diseases such as Zika, dengue and chikungunya.
• A new initiative thus aims at reducing the population of Aedes aegypti mosquito.
• It comes from the Mumbai-based company, Gangabishan Bhikulal Investment and Trading Limited (GBIT).

What is the new gene?

• Diseases such as Zika, dengue and chikungunya are transmitted when an infected, pregnant female mosquito bites somebody.
• Males do not bite and are, therefore, harmless.
• So GBIT wants to introduce a new Genetically Modified (GM) male Aedes aegypti mosquito.
• This GM insect has been bred by Oxitec, an R&D biotech company with roots in the University of Oxford.
• Oxitec has bio-engineered a transgenic male Aedes aegypti mosquito.
• This carries a new gene fatal only to female mosquitoes.

What does it do?

• The idea is to release a large number of such GM male mosquitoes into the trial zone.
• These will then breed with normal females in the wild.
• In the next generation, only the males would survive and these would breed again, with normal females.
• After a few generations, the female population will be drastically reduced.
• Eventually this cycle will result in a reduction of the entire mosquito population.

Background:

Zika Virus:-

• Zika virus is a mosquito-borne flavivirus that was first identified in Uganda in 1947 in monkeys.
• It was later identified in humans in 1952 in Uganda and the United Republic of Tanzania. Outbreaks of Zika virus disease have been recorded in Africa, the Americas, Asia, and the Pacific.
• Zika virus disease is caused by a virus transmitted primarily by Aedes mosquitoes and can be passed from a pregnant woman to her foetus.
• Sexual transmission of Zika virus is also possible.
• There is no vaccine or medicine for Zika. Instead, the focus is on relieving symptoms and includes rest, rehydration and acetaminophen for fever and pain.

Dengue:-

• Dengue is transmitted by several species of mosquito within the genus Aedes.
• Symptoms include fever, headache, muscle, and joint pains, and a characteristic skin rash that is similar to measles.
• Dengvaxia is the first dengue vaccine but the Indian drug controller has yet to grant approval to it.
• India has reported 6,210 cases and six deaths from dengue until June 9, 2019.

Chikungunya:-

• Chikungunya is caused by a mosquito-borne virus.
• It is transmitted by Aedes aegypti and Aedes albopictus mosquitoes.
• Its symptoms are characterized by abrupt fever and severe joint pain, often in hands and feet, and may include headache, muscle pain, joint swelling or rash.
• There is no specific antiviral drug treatment for chikungunya.
• There is no commercial chikungunya vaccine.

CAR-T

• An 11-year-old has become the first patient to receive CAR-T therapy (immunotherapy) that uses the body’s own cells to fight cancer.
• CAR-T is a personalized form of cancer treatment.
• CAR-T involves removing immune cells and modifying them in a laboratory so they can recognize cancer cells.
• Immunotherapy is treatment that uses your body’s own immune system to help fight cancer
• First, the patient has blood removed and the white blood cells are separated out, with the rest of the blood being returned to the patient.
• A harmless virus is used to insert genes into T-cells, a special type of immune cell.
• These genes cause the T-cells to add a hook on to their surface, known as a chimeric antigen receptor (CAR).
• These engineered CAR-T cells — programmed to recognize and destroy the patient’s cancer cells — are multiplied in huge numbers and then infused back into the patient.

DANGERS OF ARTIFICIAL RIPENING OF FRUITS AND VEGETABLES

• Fruits are a good source of vitamins and minerals and play an important role in preventing Vitamin C and A deficiencies.
• WHO recommends 5 servings of fruits and vegetables every day for a healthy living.
• However, the health benefits of fruits depend on how they are ripened.
• The best course will be to allow them to ripen on the plant itself.
• The fruits become soft, change in colour and develop aroma with an increase in sugar level and reduction in acid content.
• Many factors influence the process of ripening including temperature and relative humidity.
• It is not always possible to wait for the fruit to ripen naturally.
• More often than not, they need to be transported over long distances.
• If they had been harvested in a ripe stage, they get spoilt before reaching their destination.
• For such situations, farmers harvest them much before they get ripe.
• The traders then ripen them artificially at the destination using certain chemicals.
• Most fruits produce a gaseous compound called ‘ethylene’ that starts the ripening process.
• Its level in under-ripe fruit is very low, but as the fruits develop, they produce larger amounts of the chemical that speeds up the ripening process.
• These enzymes convert complex polysaccharides into simple sugars and make the skin of the fruits soft.
• In artificial ripening, this process is mimicked using chemicals.
• The most commonly used chemical is called ‘ethephon’ (2-chloroethyl phosphonic acid).
• It penetrates into the fruit and decomposes ethylene.
• Another chemical that is regularly used is ‘Calcium carbide’, which produces ‘acetylene’, which is an analogue of ‘ethylene’.
• It is, however, fraught with several problems.
• Studies have shown that it breaks down the organic composition of vitamins and other micronutrients.
• Besides, it changes only the skin colour, the fruit remains raw inside.
• Industrial grade calcium carbide is often found contaminated with traces of arsenic and phosphorus which are toxic chemicals.
• The symptoms of arsenic and phosphorous poisoning include,

1) Vomiting, diarrhoea with/without blood, weakness, burning sensation in the chest and abdomen, eye damage, ulcers.

• According to studies, Calcium carbide can also affect the neurological system.
• FSSAI has banned calcium carbide under the “Prevention of Food Adulteration (PFA) Act, 1954”.
• To distinguish the artificially ripened fruit,

2) They will have uniform skin colour in fruits like tomato, mango, papaya, and in the case of banana,

3) The fruit will be yellow while the stem will be dark green.

4) If the fruits are available before season, it could mean they are artificially ripened.

• Washing and peeling the fruits before eating can minimise the risks of calcium carbide. Read more..