The Messy Story behind the Most Beautiful Experiment in Biology

2017 ◽  
Author(s):  
Douglas Allchin
Keyword(s):  
Molecular Structure ◽  
Genetic Information ◽  
Double Helix ◽  
Genetic Material ◽  
The Other ◽  
Aesthetic Response ◽  
Dna Molecule ◽  
Francis Crick ◽  
History Of ◽  
Complete Set

“The most beautiful experiment in biology.” That was how John Cairns described it: the 1958 experiment that showed how the genetic material, DNA, replicates. The work is still widely celebrated, sometimes in introductory biology textbooks. This esteemed experiment by Matt Meselson and Frank Stahl (described more fully below) and others like it reflect an ideal in science, one marked by an intuitive aesthetic response. The test was simple. The results were clear. The method and reasoning seemed obvious. Theory and evidence complemented each other elegantly. That seems to be how science works—or should work. However, this view of biology, so common as to be beyond question—another sacred bovine?—can be misleading. Appearances can be deceptive. Delving into the history of this now-famous experiment fosters a very different image. Behind the apparent simplicity hides extraordinary—and fascinating—complexity. A glimpse of the messy world of investigation indicates how science really happens, quite apart from the tidy scientific method that one finds in standard textbooks. Ultimately, the messy story behind the most beautiful experiment in biology offers a quite different, and deeply informative, way to appreciate science. The experiment developed from a puzzle about how DNA, the genetic molecule, replicates. In 1953 James Watson and Francis Crick, building on data from Rosalind Franklin and Maurice Wilkins, presented a model of DNA’s molecular structure. It was two threads that coiled around each other, they claimed. Like two intertwined strands of rope. That double helix model has since been widely celebrated and inspired much art. But how did the DNA molecule replicate? When any cell divides, each new cell receives a complete set of information. Duplicate copies of DNA are assembled. Watson and Crick had only hinted at how that might occur. The genetic information was a sequence of units, called nucleotides, that bridged the two strands. They occurred in pairs. The shapes in each pair were complementary. So the shape of one side would determine which missing base would pair on the other.

CHIASMUS IN ART AND TEXT

2013 ◽  
Vol 60 (1) ◽  
pp. 50-88
Author(s):  
Edmund Thomas
Keyword(s):  
Molecular Structure ◽  
Twentieth Century ◽  
Nucleic Acid ◽  
Nucleic Acids ◽  
Double Helix ◽  
Scientific Article ◽  
Deoxyribose Nucleic Acid ◽  
Francis Crick

Sixty years ago, on 25 April 1953, probably the most influential scientific article of the twentieth century appeared. Its uninviting title, ‘Molecular Structure of Nucleic Acids: A Structure for Deoxyribose Nucleic Acid’, concealed the revolutionary discovery by the molecular biologists James Watson and Francis Crick of the structure of what became known as ‘the molecule of life’. The ‘radically different structure’ that they proposed for the salt of deoxyribose nucleic acid (DNA) had ‘two helical chains each coiled round the same axis’. ‘Both chains’, they wrote, ‘follow right-handed helices, but owing to the dyad the sequences of the atoms in the two chains run in opposite directions.’ When Bruno J. Strasser asked in the same journal fifty years later ‘Who cares about the double helix?’, he answered that it marked ‘an age of (lost) innocence, when youth, intelligence and self-assurance were sufficient to make great discoveries in science’.

1. The early milestones

2016 ◽  
Author(s):  
Aysha Divan ◽  
Janice A. Royds
Keyword(s):  
Molecular Biology ◽  
Charles Darwin ◽  
Double Helix ◽  
Francis Crick ◽  
Alfred Russel Wallace ◽  
History Of ◽  
Double Helix Structure ◽  
Evolution By Natural Selection ◽  
Evolution Of Ideas ◽  
Molecular Nature

Molecular biology is the story of the molecules of life, their relationships, and how these interactions are controlled. ‘Early milestones’ first explores two key ideas in the early history of molecular biology that provided inspiration at the start of the hunt for the molecular nature of the transmissible factors that provide continuity of life: evolution by natural selection as proposed by Charles Darwin and Alfred Russel Wallace; and Gregor Mendel’s work on heritable factors. The evolution of ideas and the development of techniques that led to the key finding of the double helix structure of DNA by James Watson and Francis Crick in 1953 are also described.

scholarly journals The History and Challenges of Women in Genetics: A Focus on Non-Western Women

2021 ◽  
Vol 12 ◽  
Author(s):  
Hadeel Elbardisy ◽  
Malak Abedalthagafi
Keyword(s):  
International Development ◽  
Double Helix ◽  
Human Life ◽  
Gender Disparity ◽  
Western World ◽  
X Ray Crystallography ◽  
Francis Crick ◽  
History Of ◽  
Barbara Mcclintock ◽  
Diverse Cultures

“Women in much of the world lack support for fundamental functions of a human life.” This truthful portrait was pointed out by Martha Nussbaum in her book “Introduction: Feminism & International Development.” Throughout history, gender inequality has been persistent in many aspects of life, including health and empowerment. Unfortunately, this inequality has not been excluded from the field of science. Perpetual assumption that women’s absence or restriction to secondary roles in various disciplines is an acceptable law of nature misrepresents women’s contribution to science and maintains hurdles for participation in the future. According to a recent UNESCO’s report, women make up only 30% of researchers worldwide. But despite all the obstacles, women made major contributions with discoveries that shaped the progress in many scientific fields. In the field of genetics, Rosalind Franklin is an example of unwittingly compromised women’s scientific achievements. Franklin was an expert in X-ray crystallography; her data, especially the “photo 51,” was critical to James Watson and Francis Crick along with their own data to publish the discovery of the double helix DNA structure in 1953. Her contribution was acknowledged posthumously in Watson’s memoir in 1968. Barbara McClintock was a 20th century American cytogeneticist who remains up to date the only woman receiving an unshared Nobel prize in Physiology or Medicine. McClintock dedicated her work to cytogenetics and discovered the phenomenon of mobile genes. Her research was initially subjected to skepticism in the 1950s. It was not until the late 1960s that the community realized the significance of McClintock’s discovery. The history of science is occupied with a myriad of similar tales of such inspiring women that, after tremendous struggles, thrived and achieved breakthroughs in their respective fields. It is prominent our limited knowledge of women’s experience and struggle in science in non-western world. Addressing the stories of this outstanding minority is critical to expand the understanding of the gender disparity factors embedded in diverse cultures. In this article, we attempt to put the spotlight on some fascinating non-western women and their significant contributions to the field of genetics.

scholarly journals Understanding biochemistry: structure and function of nucleic acids

2019 ◽  
Vol 63 (4) ◽  
pp. 433-456 ◽  
Author(s):  
Steve Minchin ◽  
Julia Lodge
Keyword(s):  
Nucleic Acids ◽  
Genetic Information ◽  
Deoxyribonucleic Acid ◽  
Double Helix ◽  
Protein Translation ◽  
Structure And Function ◽  
Dna Molecule ◽  
Living Things ◽  
Dna Double Helix ◽  
And Function

Abstract Nucleic acids, deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), carry genetic information which is read in cells to make the RNA and proteins by which living things function. The well-known structure of the DNA double helix allows this information to be copied and passed on to the next generation. In this article we summarise the structure and function of nucleic acids. The article includes a historical perspective and summarises some of the early work which led to our understanding of this important molecule and how it functions; many of these pioneering scientists were awarded Nobel Prizes for their work. We explain the structure of the DNA molecule, how it is packaged into chromosomes and how it is replicated prior to cell division. We look at how the concept of the gene has developed since the term was first coined and how DNA is copied into RNA (transcription) and translated into protein (translation).

Electron microscopic assays of restriction endonuclease cutting, exonuclease digestion, and hybridization

1984 ◽  
Vol 42 ◽  
pp. 686-687
Author(s):  
Mark Hannibal ◽  
Jacob Varkey ◽  
Michael Beer
Keyword(s):  
Electron Microscope ◽  
Low Temperature ◽  
Restriction Endonuclease ◽  
Double Helix ◽  
Test Material ◽  
Electron Microscopic ◽  
Exonuclease Iii ◽  
Dna Molecule ◽  
Linear Molecules ◽  
Exonuclease Digestion

Workman and Langmore have recently proposed a procedure for isolating particular chromatin fragments. The method requires restriction endonuclease cutting of the chromatin and a probe, their digestion with two exonucleases which leave complimentary single strand termini and low temperature hybridization of these. We here report simple electron microscopic monitoring of the four reactions involved.Our test material was ϕX-174 RF DNA which is cut once by restriction endonuclease Xho I. The conversion of circles to linear molecules was followed in Kleinschmidt spreads. Plate I shows a circular and a linear DNA molecule. The rate of cutting is shown in Figure 1.After completion of the endonuclease cutting, one portion of the DNA was treated with exonuclease III, an enzyme known to digest the 3' terminals of double helical DNA. Aliquots when examined in the electron microscope reveal a decreasing length of double helix and increasing bushes at the ends.

Activity of Plasmin and Streptokinase-Activator on Substituted Arginine and Lysine Esters

1966 ◽  
Vol 16 (01/02) ◽  
pp. 018-031 ◽  
Author(s):  
S Sherry ◽  
Norma Alkjaersig ◽  
A. P Fletcher
Keyword(s):  
Molecular Structure ◽  
Methyl Ester ◽  
Comparative Studies ◽  
Esterase Activity ◽  
Methyl Esters ◽  
Hydrolytic Activity ◽  
The Other ◽  
Other Hand

SummaryComparative studies have been made of the esterase activity of plasmin and the streptokinase-activator of plasminogen on a variety of substituted arginine and lysine esters. Human plasmin preparations derived by different methods of activation (spontaneous in glycerol, trypsin, streptokinase (SK) and urokinase) are similar in their esterase activity; this suggests that the molecular structure required for such esterase activity is similar for all of these human plasmins. Bovine plasmin, on the other hand, differs from human plasmin in its activity on several of the substrates studied (e.g., the methyl esters of benzoyl arginine and tosyl, acetyl and carbobenzoxy lysine), a finding which supports the view that molecular differences exist between the two animal plasmins. The streptokinase-activator hydrolyzes both arginine and lysine esters but the ratios of hydrolytic activity are distinct from those of plasmin and of other activators of plasminogen. The use of benzoyl arginine methyl ester as a substrate for the measurement of the esterase activity of the streptokinase-activator is described.

Theodor W. Adorno

2018 ◽  
Author(s):  
Colby Dickinson
Keyword(s):  
The Other ◽  
History Of Thought ◽  
History Of ◽  
The One

In his somewhat controversial book Remnants of Auschwitz, Agamben makes brief reference to Theodor Adorno’s apparently contradictory remarks on perceptions of death post-Auschwitz, positions that Adorno had taken concerning Nazi genocidal actions that had seemed also to reflect something horribly errant in the history of thought itself. There was within such murderous acts, he had claimed, a particular degradation of death itself, a perpetration of our humanity bound in some way to affect our perception of reason itself. The contradictions regarding Auschwitz that Agamben senses to be latent within Adorno’s remarks involve the intuition ‘on the one hand, of having realized the unconditional triumph of death against life; on the other, of having degraded and debased death. Neither of these charges – perhaps like every charge, which is always a genuinely legal gesture – succeed in exhausting Auschwitz’s offense, in defining its case in point’ (RA 81). And this is the stance that Agamben wishes to hammer home quite emphatically vis-à-vis Adorno’s limitations, ones that, I would only add, seem to linger within Agamben’s own formulations in ways that he has still not come to reckon with entirely: ‘This oscillation’, he affirms, ‘betrays reason’s incapacity to identify the specific crime of Auschwitz with certainty’ (RA 81).

The World after the End of the World

2017 ◽  
Vol 39 (2) ◽  
pp. 265-276 ◽  
Author(s):  
Kas Saghafi
Keyword(s):  
The Other ◽  
The World ◽  
History Of ◽  
The Absolute ◽  
End Of The World

In several late texts, Derrida meditated on Paul Celan's poem ‘Grosse, Glühende Wölbung’, in which the departure of the world is announced. Delving into the ‘origin’ and ‘history’ of the ‘conception’ of the world, this paper suggests that, for Derrida, the end of the world is determined by and from death—the death of the other. The death of the other marks, each and every time, the absolute end of the world.

Med. Dr. Adalbert Wraný (1836–1902) – doctor of medicine, mineral collector and donor to the National Museum in Prague

2019 ◽  
Vol 188 (1) ◽  
pp. 95-146
Author(s):  
Martin Bohatý ◽  
Dalibor Velebil
Keyword(s):  
Natural Science ◽  
Natural Sciences ◽  
The Other ◽  
National Museum ◽  
Industrial Chemistry ◽  
Pediatric Pathology ◽  
Geological Institute ◽  
History Of ◽  
Precious Stones

Adalbert Wraný (*1836, †1902) was a doctor of medicine, with his primary specialization in pediatric pathology, and was also one of the founders of microscopic and chemical diagnostics. He was interested in natural sciences, chemistry, botany, paleontology and above all mineralogy. He wrote two books, one on the development of mineralogical research in Bohemia (1896), and the other on the history of industrial chemistry in Bohemia (1902). Wraný also assembled several natural science collections. During his lifetime, he gave to the National Museum large collections of rocks, a collection of cut precious stones and his library. He donated a collection of fossils to the Geological Institute of the Czech University (now Charles University). He was an inspector of the mineralogical collection of the National Museum. After his death, he bequeathed to the National Museum his collection of minerals and the rest of the gemstone collection. He donated paintings to the Prague City Museum, and other property to the Klar Institute of the Blind in Prague. The National Museum’s collection currently contains 4 325 samples of minerals, as well as 21 meteorites and several hundred cut precious stones from Wraný’s collection.

La ética del Otro: una introducción al pensamiento de Emmanuel Lévinas

2019 ◽  
Vol 1 (1) ◽  
pp. 5-14
Author(s):  
Carlos Alvaréz Teijeiro
Keyword(s):  
Interpersonal Relationships ◽  
Emmanuel Levinas ◽  
Radical Change ◽  
The Other ◽  
Western Philosophy ◽  
Ethical Implications ◽  
Essential Question ◽  
History Of ◽  
The Relationship ◽  
First Philosophy

Emmanuel Lévinas, the philosopher of ethics par excellence in the twentieth century, and by own merit one of the most important ethical philosophers in the history of western philosophy, is also the philosopher of the Other. Thereby, it can be said that no thought has deepened like his in the ups and downs of the ethical relationship between subject and otherness. The general objective of this work is to expose in a simple and understandable way some ideas that tend to be quite dark in the philosophical work of the author, since his profuse religious production will not be analyzed here. It is expected to show that his ideas about the being and the Other are relevant to better understand interpersonal relationships in times of 4.0 (re)evolution. As specific objectives, this work aims to expose in chronological order the main works of the thinker, with special emphasis on his ethical implications: Of the evasion (1935), The time and the Other (1947), From the existence to the existent (1947), Totality and infinity: An essay on exteriority (1961) and, last, Otherwise than being, or beyond essence (1974). In the judgment of Lévinas, history of western philosophy starting with Greece, has shown an unusual concern for the Being, this is, it has basically been an ontology and, accordingly, it has relegated ethics to a second or third plane. On the other hand and in a clear going against the tide movement, our author supports that ethics should be considered the first philosophy and more, even previous to the proper philosophize. This novel approach implies, as it is supposed, that the essential question of the philosophy slows down its origin around the Being in order to inquire about the Other: it is a philosophy in first person. Such a radical change of perspective generates an underlying change in how we conceive interpersonal relationships, the complex framework of meanings around the relationship Me and You, which also philosopher Martin Buber had already spoken of. As Lévinas postulates that ethics is the first philosophy, this involves that the Other claims all our attention, intellectual and emotional, to the point of considering that the relationship with the Other is one of the measures of our identity. Thus, “natural” attitude –husserlian word not used by Lévinas- would be to be in permanent disposition regarding to the meeting with the Other, to be in permanent opening state to let ourselves be questioned by him. Ontology, as the author says, being worried about the Being, has been likewise concerned about the Existence, when the matter is to concern about the particular Existent that every otherness supposes for us. In conclusion it can be affirmed that levinasian ethics of the meeting with the Other, particular Face, irreducible to the assumption, can contribute with an innovative looking to (re)evolving the interpersonal relationships in a 4.0 context.

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