Correspondence
According to some in the field, one should refrain from discussions concerning controversial issues in science if one is not actively conducting experimental research1. We must dissent, most particularly when the prions controversy is under consideration. One does not have to conduct scientific experiments to recognize not only the flaws of the prion protein (PrP) hypothesis2, but the inappropriate vocabulary used during discussions of the issue. As science educators, we are still confounded when trying to present the cause of Transmissible Spongiform Encephalopathy (TSE) to our students.
To start with, for the past twenty years, the majority of biology text books unequivocally identified PrPSc as the causative agent of TSE, and some texts even refer to the “prion hypothesis” as the “prion theory”, please see Table 1. Yet, when introducing the scientific method in high schools and college classes, we establish that in order for a hypothesis to become a scientific theory, it has to be supported many times over through experimentation3 providing a substantial and conclusive body of evidence4. Upon reviewing experimental work on PrP, one notes that initial studies are rarely, if ever, repeated by other scientists. Instead, they move on without giving reconsideration to the assumption upon which they base their work5.
Table 1. The indisputable textbook statements concerning infectious agent of Transmissible Spongiform Encephalopathies.
| Authors | Name of the textbook | Publishing company | Year of the
publication | Statements |
|---|
McKee T.,
McKee J.R. | Biochemistry: The
molecular Basis of Life | McCraw Hill | 2003 | “Prion disease are caused when the conformation of PrPC is
converted to PrPSc”. |
Gladwin M.,
Trattler W. | Clinical Microbiology
Made Ridiculously Simple | MedMaster | 2004 | “The prion-only hypothesis is the most widely accepted
theory today”. |
| Freeman S. | Biological Science | Pearson Benjamin
Cummins | 2008 | “Over the past several decades, evidence has accumulated
that certain proteins can act as infectious, disease causing
agents”. |
Russell P.J.,
Wolfe S.L.,
Hertz P.E.,
Starr C.,
McMillan B. | Biology: the Dynamic
Science | Thomson
Brooks/Cole | 2008 | “Prions … are the only known infectious agents that do
not include a nucleic acid molecule”.
“Prions have been identified as the causal agents of
certain diseases that degenerate the nervous system in
mammals”. |
Campbell M.K.,
Farrell S.O. | Biochemistry | Thomson
Brooks/Cole | 2009 | “It has been established that the causative agent of
mad-cow disease, as well as the related diseases scrapie
in sheep, chronic wasting (CWD) in deer and elk, and
human spongiform encephalopathy in humans is a small
(28-kDa) protein called a prion”. |
Tymoczko J.L.,
Berg J.M.,
Lubert S. | Biochemistry: A Short
Course | W.H. Freeman &
Company | 2010 | “Certain infectious neurological diseases were found
to be transmitted by agents that were similar in size to
viruses but consisted only of protein”. |
| Talaro K.P. | Foundations in
Microbiology | McGrow Hill | 2009 | “Prions are incredibly hardy “pathogens”. They are known
to cause diseases called transmissible spongiform
encephalopathies”. |
Cowan M.K.,
Bunn J. | Microbiology
Fundamentals: A Clinical
Approach | McGrow Hill | 2013 | “The transmissible agent in CDJ is a prion”. |
Tortora G.J.,
Funke B.R.,
Case C.L. | Microbiology: An
Introduction | Pearson | 2013 | “Several fatal diseases affecting the human central
nervous system are caused by prions”. |
When describing the scientific method, it is important that we emphasize the difference between faith and fact. Nevertheless, during discussions of the PrP hypothesis in meetings, conferences and private discussions of scientists, “I think” is too often replaced by “I believe”. Perhaps, this inclination began when the Karolinka neurologist Lars Edison told The Times newspaper upon the announcement of the Prusiner’s Noble Prize: “There are still people who don’t believe that a protein can cause these diseases, but we believe it”6. There should be no place in science for such a subjective declaration. Even recent publications emphasize that the scientific community has been split into PrP “believers” and “nonbelievers”. Laura Manuelidis, one of the main scientists who rejects the PrP hypothesis, has been portrayed as a “prion heretic”7. Upon entering the combination of “prions” and “belief” in a Google search, we generated an astonishing 918,000 hits. Another recent tendency in modern science is marginalizing scientists as the “minority” versus the “majority” as is seen in the PrP controversy7, a partition more suitable for political rather than scientific discussions.
In covering the PrP hypothesis in classrooms, are we also to employ a vocabulary in which the scientific community is divided into “believers” and “nonbelievers” or “majority” and “minority” as if we were referring to a religious conviction or a political debate rather than a scientific dilemma?
Author contributions
IVZ was involved in reviewing the literature and writing the letter. LC, SB-W, MP, SNS, AGP and OVW equally contributed to the emerged discussion and conceptualization of the paper and all approved the final version of the manuscript.
Competing interests
No competing interests were disclosed.
Grant information
The author(s) declared that no grants were involved in supporting this work.
References
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AAAS: Live Chat: When you’re in the Scientific Minority.
Science.
2011. Reference Source
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Zaitsev IV:
Prions: Introducing a Complex Scientific Controversy to a Biology Classroom.
Am Biol Teach.
2009; 71(9): 525–530. Publisher Full Text
- 3.
Campbell NA, Reece JB:
Biology. Pearson Educational, Inc. as Benjamin Cummings, San Francisco 2005. Reference Source
- 4.
Medley D:
Biology: Reviewing the Essentials. AMSCO School Publications, Inc., New York 1998. Reference Source
- 5.
Zaitsev IV:
Could Prion Protein Assumptions Engender Misleading Sensational Conclusions? 2010. Reference Source
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Rhodes R:
Deadly Feasts. Simon & Schuster 1997. Reference Source
- 7.
Couzin-Frankel J:
The prion heretic.
Science.
2011; 332(6033): 1024–1027. Publisher Full Text
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Vitaly Citovsky
Department of Biochemistry and Cell Biology
State University of New York
Stony Brook, NY 11794-5215
Tel.: 631.632.9534
Fax: 631.632.8575
E-mail: vitaly.citovsky@stonybrook.edu
--------------------------
Vitaly Citovsky
Department of Biochemistry and Cell Biology
State University of New York
Stony Brook, NY 11794-5215
Tel.: 631.632.9534
Fax: 631.632.8575
E-mail: vitaly.citovsky@stonybrook.edu