50 years ago today Johnson signed MediCare into law

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On this day in 1965, President Lyndon B. Johnson signed Medicare, a health insurance program for elderly Americans, into law. At the bill-signing ceremony, which took place at the Truman Library in Independence, Missouri, former President Harry S. Truman was enrolled as Medicare’s first beneficiary and received the first Medicare card. Johnson wanted to recognize Truman, who, in 1945, had become the first president to propose national health insurance, an initiative that was opposed at the time by Congress.

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Throw Back Thursday: 112 years ago today Marie Curie announces her discovery of Radium

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Marie Curie (Maria Sklodowska-Curie) was the first person in history to obtain two Nobel Prizes in different areas of science (physics and chemistry). Born in Warsaw, Poland, Marie Curie was the first woman appointed to teach at La Sorbonne (University of Paris) and the first woman in France to achieve her doctoral degree.

She succeeded in separating radium from barium only with tremendous difficulty. The shed in which this momentous discovery took place, formerly a medical school dissecting room, was poorly outfitted and ventilated. It took Marie over three years to isolate one tenth of a gram of pure radium chloride, for reasons that would not be fully understood until the concept of radioactive decay was developed.

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Then and now: the final part of our biochemistry in the 80s series

In the 1980s a three-part series of videos was published by Portland Press on behalf of the Biochemical Society. ‘The Biochemical Basis of Biology’ video series aimed to present biochemical facts and concepts in a dynamic way to students in further and higher education.

To see how biochemistry knowledge and techniques have changed in the last 30 years, we asked members of the Biochemical Society to review these videos and to write a short text comparing them to where we are today.

Today Dr Gerhard May, from our Education Committee, looks at the final video DNA and Protein Synthesis, produced by E.M Evans and E.J Wood. You can see posts about the previous two videos here.

DNA and Protein Synthesis

Guest post by Dr Gerhard May

This video made in 1987 and titled ‘DNA and Protein Synthesis’, is split into three sections. These sections are loosely connected to each other and can easily be viewed in isolation, however, parts 1 and 3 provide historical perspectives supporting the molecular concepts described in part 2.

Part 2 of the video, entitled ‘Mechanism of protein synthesis’, gets to the heart of the matter and describes what Francis Crick had originally termed ‘The Central Dogma’. It clearly describes the basic structure of DNA and how the 4 nucleotides are used in triplets to encode the sequence of amino acids in a protein. It nicely illustrates how DNA is transcribed into messenger RNA and how this is translated (with the help of ribosomal and transfer RNAs) into protein. Although the animation is a little dated and the narration a bit slow, this information remains central to biochemistry, molecular biology and genetics and all biology students will need to understand this process. What it doesn’t describe, because this was not known about at the time, are the multiple other types of non-coding RNAs that regulate gene expression; in particular, the very small RNAs (called microRNAs, only about 22 nucleotides long), that act to inhibit the production of protein.

The first part of the video shows an experiment to demonstrate that protein is made from amino acids, by components present in the cytoplasm of a cell. Thirty years ago, this could only be accomplished in the laboratory by radio-labelling amino acids and ‘following’ the radioactivity. Therefore, much of the video comprehensibly explains the nature of radioisotopes and how they can be detected. While radioisotopes are still used to some extent in biology labs today, for most applications they have been supplanted by safer, better and more versatile methods to label biomolecules. For example, proteins can be detected directly using fluorescent labels or using antibodies to specific proteins. The labelled antibodies can then be visualised by fluorescent, chemiluminescent or even infra-red methods. DNA sequencing methods have massively advanced since the making of this video, when sequencing 400 nucleotides required a full day and a big acrylamide gel, using radioactive nucleotides (as shown). Now 2nd ‘next generation’ sequencing methods permits the parallel sequencing of thousands of molecules, using optical methods of detection (including fluorescent or luminescent labelled nucleotides) or non-optical methods, for example detection of hydrogen ion release. This area continues to progress at a pace, and 3rd generation methods, including labelling nucleotides with heavy elements (such as halogens) and detection by atomic force microscopy is just one approach of many under development.

The third section of the video describes a classical experiment to show that DNA, and not protein, carries the heritable information of a cell, a fact that we all take for granted now. In the early 1950s, before the structure of DNA was known, it wasn’t clear how heritable information was passed on and it was not easy to find out. To understand how the 1952 Hershey and Chase experiment was conducted, some knowledge about viruses that infect bacteria (bacteriophages) is required, which the video provides. Again, radioisotopes are used to label and track the bacteriophage DNA. The Hershey-Chase experiment is still mentioned in passing during undergraduate degree programmes in the biomolecular sciences. It is an excellent example of the use of radioactivity in molecular biology, and is of particular historic interest for anyone who wants to learn more about ‘how on earth did they find this out’. Watching this video will not only teach you some basic concepts in molecular biology, but also demonstrate some aspects of the techniques that were used to unravel those concepts.

Then and now: Continuing our look at biochemistry in the 80s

In the 1980s a three-part series of videos was published by Portland Press on behalf of the Biochemical Society. ‘The Biochemical Basis of Biology’ video series aimed to present biochemical facts and concepts in a dynamic way to students in further and higher education.

To see how biochemistry knowledge and techniques have changed in the last 30 years, we asked members of the Biochemical Society to review these videos and to write a short text comparing them to where we are today.

Following on from Dr Helen Watson’s review of Cell Structure and Energy Production, today Dr Joanna Wilson (University of Glasgow) looks at the second video Manipulating DNA. Keep an eye out on our blog for a commentary on the final video, DNA and Protein Synthesis, in the coming weeks.

Manipulating DNA

Guest post by Dr Joanna Wilson, University of Glasgow

This video, made in 1994, shows some fundamental techniques in molecular biology, used to manipulate DNA. It is divided into four sections covering [1] restriction digestion (cutting DNA), [2] agarose gel electrophoresis (separating DNA fragments by size), [3] the polymerase chain reaction (PCR, used to amplify tiny quantities of DNA) and [4] cloning DNA (permitting archiving, production and manipulation of specific DNA fragments, as well as expression of genes). Although the video is now over 20 years old, the basic concepts described and many of the techniques used, are central to molecular biology and are still used in labs around the world today.

Some protocol aspects have changed since the making of this video, in particular the methods are now faster and safer, but approaches such as these have led to a revolution in molecular biology, such that, although still used, these techniques now form just one small part of a huge armoury of DNA technology.

So how exactly have the specific techniques shown improved today? Much of the equipment used, such as the powerpacks (for gel ecletrophoresis), the thermocycler (for PCR), the gel camera system, are more efficient, smaller, sleeker, usually computerised and certainly more versatile. For example, gel imaging systems are linked to computers now, for digital image production (instead of taking an analogue photo and having to produce an instamatic print). Thermocyclers have heated lids (no need for oil on top of the PCR sample) to prevent evaporation and maintain precise temperatures and they can be programmed to run multiple temperature parameters at once. Safety in molecular protocols has improved immensely over the past decades. For example, Bunson burners are almost a thing of the past; the method to spread bacteria on an agar plate using an ethanol and flame sterilised spreader – simply replaced now with a disposable plastic spreader (no open flame and alcohol). Although still widely used, several labs have replaced ethidium bromide (a nasty mutagen) to visualise DNA, with safer dyes. One of the biggest changes since 1994 is evident in the method to purify plasmid DNA. In section [4], we see how to make a caesium chloride density gradient to purify the plasmid. I winced when we were shown the use of a sharp needle to collect the DNA, full of mutagenic ethidium bromide, even though this was a method I used to conduct routinely. Just one needle slip would have been very nasty. So what do we use now? We buy a DNA purification kit from a biotechnology company, containing a little column to allow purification of the DNA by its charge (remember it is negative) and in a matter of an hour, we have nice clean DNA, no big ultra-centrifuge for over-night spins, no toxic and mutagenic substances – easy.

What about the molecular revolution? The protocol shown in the first section shows how to cut DNA in a test tube. The use of restriction enzymes is still a corner stone in the lab. But more than this, DNA can now be manipulated in almost every way imaginable.  It can be cut, bits deleted or changed, glued, twisted and flipped, in a test tube and amazingly, even within a living cell. While the principles of PCR, shown in section [3], haven’t changed a jot, the enormity of PCR application was not realised at that time. For example, modern day forensics would be unrecognisable 20 years ago, when PCR was still in its infancy. Now an individual can be identified from a hair or speck of blood using PCR followed by “DNA fingerprinting”. Using PCR, even ancient DNA from Neanderthal man has been analysed and this allows us to work out the evolutionary relationship of Neanderthals with us. PCR and other DNA polymerisation wizardry has also revolutionised DNA sequencing. It took over 10 years to sequence the first human genome, now it takes just a few days and given enough sequencing machines, multiple genomes can be read at once. This exemplifies an area of major advancement in molecular biology. Many of the techniques that can be conducted by one person in a lab, as shown in the video, have advanced to the point where much can be automated and robotic machines conduct the work with very high throughput. The single scientist in the lab is far from redundant, but we can leave a lot of the boring work to machines and biotechnology companies and use kits to speed through our bright ideas.

Then and now: A look back at biochemistry in the 80s

In the 1980s a three-part series of videos was published by Portland Press on behalf of the Biochemical Society. ‘The Biochemical Basis of Biology’ video series aimed to present biochemical facts and concepts in a dynamic way to students in further and higher education.

To see how biochemistry knowledge and techniques have changed in the last 30 years, we asked members of the Biochemical Society to review these videos and to write a short text comparing them to where we are today.

Today Dr Helen Watson, from our Education Committee, looks at the first video Cell Structure and Energy Production, produced by E.M Evans and E.J Wood. Keep an eye out on our blog for commentaries on the next video – DNA and Protein Synthesis and Manipulating DNA – in the coming weeks.

Cell Structure and Energy Production

Guest blog by Dr Helen Watson, University of Exeter

This video shows some of the techniques that were used in biochemistry and cell biology to understand cell structure and the function of enzymes in animal and plant cells. As you will see, we have come a long way since this video was made (and not only in haircuts!).

Variations on most of the techniques shown in the video are still used in labs today. In the years since this video was made, big advances in technology have enabled biologists to work with computer controlled equipment rather than doing everything manually. You’ll notice there is no computer attached to the microscope in the video. In modern labs, electron microscopes (and most other microscopes) are attached to computers which enable us to focus images, capture images and build up 3D models of samples so we can better understand the structures inside cells. Techniques such as confocal microscopy and FRET have become common and help us to understand the ultrastructure of cells, including where proteins are located and which proteins interact with each other. The use of fluorescent proteins has been vital in helping us to work out where proteins are localised inside cells and how they move about and interact with each other.

Our knowledge of protein structure has informed our understanding of protein function. We now know the 3D structures of many of the enzymes mentioned in the oxidative phosphorylation pathway. X-ray crystallography and other structural techniques like NMR have told us a huge amount about how enzymes like these function and, in this case, make energy. In the video, oxidative phosphorylation appears as a ‘black box’. Now, thanks in part to structural studies, we know much more about the enzymes and which parts of the reaction they catalyse.

We now know the sequence of the human genome and genomes of many other organisms. Having the technology to quickly manipulate and sequence DNA has enabled biochemistry and cell biology to move at a rapid pace. We can now easily study proteins one at a time by manipulating the gene that codes for them and synthesising the protein in a test tube (in vitro). This has, to some extent, made it unnecessary to fractionate cells and look at organelles, although this is still done in some experiments.

It is interesting to see which techniques have changed and which have remained the same since this video was made. Much of the equipment here is now a lot more advanced. Our microscopes now have computers attached to them to help us focus, record and quantify images. However, lots of the machines and techniques here such as the centrifuges and cell fractionation are still used on a daily basis in biochemistry and cell biology labs today. This video highlights just how fast research and technology in biological sciences moves and what an exciting, dynamic and sometimes unpredictable field it is to work in.