Category Biochemistry

Loring and Schwerdt search for a virus

If the year 2020 taught us anything, it is to serve as a reminder that humanity isn’t all powerful and that we are just a tiny speck in the vast timeline of our universe. For not even in our wildest dreams would we have imagined that a virus would lockdown the majority of humankind at the same time.

The reason for this, as you obviously know, is the coronavirus. The disease might have been named COVID-19 for COronaVIrus Disease 2019, but the pandemic raged through 2020 and shows little signs of abating even now in 2021. This, despite the fact that a mountain load of human resources, on top of huge financial impetus, has been funnelled towards the cause of checking the spread of the disease.

Nature of the problem

In case you, or anyone around you, are wondering why it is taking us so long to find a fix, it is important to remember that that is indeed the nature of this problem. It isn’t the first one confronting us and a look at the poliovirus would illustrate it further.

Poliovirus is the causative agent of polio, a highly infectious disease that can totally paralyse a person in a few hours and is especially lethal against children under the age of five. If you ask the elders at your house, they would tell you that you too were administered a vaccine against the poliovirus as a child.

Our fight against the poliovirus, which is still ongoing, has spanned over decades. From affecting nearly 3,50,000 in over 125 countries even as recently as 1988, the numbers have dropped down to hundreds in the recent years. We have many people to thank along the way… Stanford scientists Hubert Scott Loring and Carlton Everett Schwerdt among them.

Loring’s laboratory

In the fall of 1939, with the world about to be embroiled in World War II, Professor Loring joined the faculty of the Stanford University Chemistry Department. His important research activities here took place in the early and mid-1940s.

Loring’s laboratory was characterised by a friendly atmosphere and subdued excitement. With his students, he was involved in two major areas during this time – the purification of the poliomyelitis virus and the structure and metabolism of ribonucleic acids.

Along with his student Schwerdt, Loring spent three years searching for the poliovirus. Their efforts led to the successful isolation of the Lansing strain of the poliovirus in 1946. Schwerdt completed his Ph.D. in biochemistry by the time their results were announced on January 10, 1947.

Tempers excitement

Loring and Schwerdt were able to obtain the virus with at least 80% purity. They were able to extract it from cotton rats, the only species then known to contract polio other than primates. Even though they had opened the door to further experimentation and the development of a vaccine against polio, Loring tempered the excitement, cautioning that the path ahead might still be long.

They were able to come up with a crude vaccine against polio in cotton rats later in 1947 before Schwerdt switched to the Virus Laboratory of the University of California at Berkeley. Here, he was able to further improve both his techniques and the product.

Working alongside his colleagues at Berkeley, Schwerdt developed a method to purify the poliovirus and also photographed it for the first time in pure form in 1953. He was involved in crystallising the pure virus in 1955 and also purified all three known major strains of poliovirus in 1957.

Our journey towards a polio-free world continues, even as the COVID-19 pandemic tries to undo some of the great work already achieved. Polio survives among the world’s poorest and marginalised, and the lockdowns and restrictions imposed to curtail the spread of coronavirus has also hindered administering vaccines against polio and other diseases to those who need it.

The work done by Loring, Schwerdt and many others ensured that the polio vaccine was safe when it came about in the 1950s. We will have countless more to thank when effective vaccines against COVID-19 also become a part of our lives.

 

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My aim is to become an eye specialist

My aim is to become an eye specialist. What qualities do I need to develop and which courses should I take up after Std X to pursue a career as an eye specialist?

To become an eye specialist, first you need to have a Bachelor of Medicine and Bachelor of Surgery (MBBS) degree. After completing MBBS, go for 2 years PG diploma or 3 years M.D. (Doctor of Medicine) in Ophthalmology or M.S. (Master of Surgery).

The duration of MBBS is 52 of which the last one year is a period years of rotary internship. Four and half years are divided into three parts. The first one and half years are spent on pre-clinical subjects, i.e., anatomy, biochemistry and physiology. The next one and a half years are spent on studies of pharmacology, forensic medicine, pathology, bacteriology, microbiology, etc. After passing the pre-clinical subjects, the next one and half years are devoted to clinical work in hospital ward and departments, concurrently with training in the para medical subjects, i.e., surgery, medicine and gynaecology. One year of internship is devoted to complete practical training in above subjects.

There are medical colleges in every state while some are controlled by central or state governments, others are administered by private communities. Admissions are either through competitive entrance exams or on merit, i.e., marks obtained in the qualifying exam.

Some of the qualities required are: strong communication skills, high degree of motivation and self-discipline, strong desire to help the sick and injured, emotional stability and the capacity to make decisions in an emergency.

 

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Who holds the record for the most spacewalks by a woman?

Peggy Annette Whitson (born February 9, 1960) is an American biochemistry researcher, retired NASA astronaut, and former NASA Chief Astronaut. Her first space mission was in 2002, with an extended stay aboard the International Space Station as a member of Expedition 5. Her second mission launched October 10, 2007, as the first female commander of the ISS with Expedition 16. She was on her third long-duration space flight and was the commander of the International Space Station for Expedition 51, before handing over command to Fyodor Yurchikhin on June 1, 2017.

The flight of Space Shuttle mission STS-120, commanded by astronaut Pam Melroy, was the first time that two female mission commanders have been in orbit at the same time. After completion of her eighth EVA in March 2017, Whitson now holds the records for the oldest woman spacewalker, and the record for total spacewalks by a woman, which was broken by her again after a ninth and tenth EVA in May 2017, surpassing Sunita Williams, who has completed 7.

Following her fellowship at Rice, she began working at Johnson Space Center in Houston, Texas, as a National Research Council Resident Research Associate. From April 1988 until September 1989, Whitson served as the Supervisor for the Biochemistry Research Group at KRUG International, a medical sciences contractor at NASA-JSC.

From 1991 through 1997, Whitson was invited to be an adjunct assistant professor in the Department of Internal Medicine and the Department of Human Biological Chemistry and Genetics at the University of Texas Medical Branch in Galveston, Texas. In 1997, Whitson began a position as adjunct assistant professor at Rice University in the Maybee Laboratory for Biochemical and Genetic Engineering.

From 1992 to 1995, she served as project scientist for the Shuttle-Mir Program and, until her selection as an astronaut candidate in 1996, as deputy division chief for the Medical Sciences division at the Johnson Space Center.

 

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Dietitian: A ‘healthy’ career choice

With the world dealing with the coronavirus pandemic, dietitians/nutritionists play a very important role in preventive healthcare. They evolve many diet regimes which help in improving immunity and controlling diseases. Today, people from all walks of life, including professionals, sportpersons, businessmen, housewives, and of course people suffering from chronic diseases visit dietitians.

The nutritionist/dietitian’s job is to research the nutritive value of food and understand all food advise people on eating habits and plan diets that will improve health.

With growing general awareness that preventive nutrition can prevent cancer, diabetes, heart attacks, etc. rather than treat a condition after it manifests itself clinically, the role of a dietitian/nutritionist has gained greater significance. Consequently, a career in this field has become attractive.

How to start

On complexion of class XII, science stream students have the option to enroll for the three-year B.Sc/BA course in nutrition but many students study dietetics only after a graduate degree in any one of the following disciplines: home science, medicine, science (with chemistry and/or microbiology), hotel management, and catering. Six-month/one-year certificate/diploma courses in nutrition are also offered by some institutes and universities. You can also sign up for correspondence courses in food and nutrition.

In B.Sc Home Science (Hons), a student can specialise in food & nutrition in the second and third year. The Honours programme admits only students from science backgrounds as its subjects include biochemistry, botany, physics, zoology and chemistry.

At the postgraduate level, you can either do a one-year post graduate diploma in Dietetics and Public Health Nutrition (DDPHN) or a two-year Master’s programme.

Skills and Aptitude

A person opting for a career as dietitian/nutritionist must have an interest in food/food preparation. He/she should also possess good communication skills to interact with people, individually and in groups. In addition he should have patience and a genuine concern for fellow beings.

Career options

  • In hospitals, dietitians work closely with doctors to prepare diet plans for patients as per their needs. They also check quality and hygiene levels in hospital kitchen.
  • In the processed food industry, a dietitian works on the development and improvement of food products and production methods.
  • In hotel industry, dietitians plan for different types of guests and also supervise food production process.
  • Spas and clinics hire dietitians to use them for designing healthy, low-calorie monthly food charts for their customers.
  • Nutritionists have a slightly different field. They work in the areas of food science, community development, research projects and FMCG companies. Their work relates to research aspect. They go beyond diets and move into the science of biochemistry and food science.

 

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WHAT ARE MOLECULES?

In nature, it is rare to find one atom on its own. Atoms are usually grouped together in larger structures called molecules. A molecule is the smallest particle of a substance that can exist by itself. The atoms in a molecule are chemically bonded together. They may be atoms of the same element or they may be of different elements. A molecule of carbon dioxide, for example, has two atoms of oxygen and one of carbon.

For millennia, scientists have pondered the mystery of life – namely, what goes into making it? According to most ancient cultures, life and all existence was made up of the basic elements of nature – i.e. Earth, Air, Wind, Water, and Fire. However, in time, many philosophers began to put forth the notion that all things were composed of tiny, indivisible things that could neither be created nor destroyed (i.e. particles).

However, this was a largely philosophical notion, and it was not until the emergence of atomic theory and modern chemistry that scientists began to postulate that particles, when taken in combination, produced the basic building blocks of all things. Molecules, they called them, taken from the Latin “moles” (which means “mass” or “barrier”). But used in the context of modern particle theory, the term refers to small units of mass.

By its classical definition, a molecule is the smallest particle of a substance that retains the chemical and physical properties of that substance. They are composed of two or more atoms, a group of like or different atoms held together by chemical forces.

It may consist of atoms of a single chemical element, as with oxygen (O2), or of different elements, as with water (H2O). As components of matter, molecules are common in organic substances (and therefore biochemistry) and are what allow for life-giving elements, like liquid water and breathable atmospheres.

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What did Hershey and Chase do in their experiment?

Often, during conversations pertaining to heredity, be it with respect to certain mannerisms or behaviour, you might have heard people allude to their DNA. This is because we now know that deoxyribonucleic acid, or DNA, holds the key to heredity to all forms of life and carries genetic instructions for the development, functioning, growth and reproduction of all known organisms and many viruses.

First isolated by Swiss physician Friedrich Miescher in 1869, DNA’s role as the carrier of life’s hereditary data wasn’t known for nearly a century. For, it was only in 1952 that it was firmly established that DNA was the substance that transmits genetic information. That was done through the Hershey-Chase experiment, also often referred to as the blender experiment.

Born in Michigan, the U.S. in 1908, Alfred Day Hershey attended public schools before going on to study B.S. in Bacteriology and doing a Ph.D. in Chemistry. He was drawn towards bacteriology and the biochemistry of life as a graduate student and even his doctoral thesis was on the chemistry of a bacteria. After receiving his Ph.D., Hershey moved into a career of research and teaching.

DNA or protein?

The foundation for the field of molecular biology was laid in the 1940s and the 1950s through research on bacteriophages. Bacteriophages, or simply phages, were known to be viruses – consisting only of DNA surrounded by a protein shell – that infect bacteria.

One of the key questions that was haunting the field was to find out which was the genetic material. The prevalent notion at the time was that it must be a protein, as its structure was complex enough to hold such data. Even though there was some research that pointed at DNA as the possible genetic material, most chemists, physicists and geneticists still held on to the then popular assumption.

Hershey, whose research on phages had provided him with a number of discoveries, set out to conclusively prove that the genetic material in phages was DNA. Along with his assistant Martha Chase, who had recently graduated, Hershey found a way to figure out the role played in replication by each of the phage components.

In experiments conducted in 1951-52, Hershey and Chase used radioactive phosphorus to tag the phage DNA and radioactive sulphur to tag the protein. These tagged phages were then allowed to infect a bacterial culture and begin the process of replication.

Role of blender

This process was interrupted at a crucial moment when the scientists whirled the culture in a blender. This was because Hershey and Chase had been able to determine that a blender produced the right shearing force to tear the phage particles from the bacterial walls, without damaging the bacteria.

Upon examination, it was clear that while the phage DNA had entered the bacterium and forced it to replicate phage particles, the phage protein was still outside, attached to the cell wall. In short, they were able to show that it was DNA, and not protein, that was responsible for communicating genetic information necessary for producing the next generation of phages.

Stimulates research

Hershey and Chase published their results on September 20, 1952. The Hershey-Chase experiment came to be popularly referred to as the blender experiment because of the fact that a simple blender had been used to achieve their test results. These results stimulated research into DNA, and within months, molecular biologists James Watson and Francis Crick published their work establishing the double helix structure of the DNA molecule. In fact, Watson wrote in a 1997 memoriam that the Hershey-Chase experiment “made me ever more certain that finding the three-dimensional structure of DNA was biology’s next important objective”. It certainly turned out to be right.

Small in size, big prize

Alfred Hershey shared the Nobel Prize in Physiology or Medicine in 1969 with Max Delbruck, a physicist who did research in the U.S. after fleeing Nazi Germany in 1937, and Salvador Edward Luria, a biologist and physician from Italy who fled to France in 1938 and immigrated to the U.S. in 1940. They received the Noble Prize for their contributions to molecular biology and their work on bacteriophages, which are viruses that infect bacteria.
Working independently, Hershey and Luria showed the occurrence of spontaneous mutation in bacteriophages and the host in 1945.
In the next year, Hershey and Delbruck separately discovered the occurrence of genetic recombination in phages. This showed that when different strains of phages infect the same bacterial cell, they can exchange or combine genetic material.
The three men turned out to be collaborators, despite the fact that they never worked together in the same laboratory.
They encouraged each other in their phage research by sharing results through correspondence and conversations.

 

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