2018 · Nature
Ring nucleases deactivate type III CRISPR ribonucleases by degrading cyclic oligoadenylate
Verdict
UNSCIENTIFIC
Neither the paradigm nor the study inside it passes. The verdict is unscientific.
1·Study methodology · inside the paradigm
UNSCIENTIFIC
Does not follow the scientific method within Molecular Biology / CRISPR Model.
2·Paradigm · Molecular Biology / CRISPR Model
UNSCIENTIFIC
Fails the tests. The worse layer decides.
How the verdict is decided
The verdict grades both layers: the paradigm this study assumes, and how the study was carried out inside it. Both must be scientific for the whole thing to be scientific. A clean method inside an unscientific paradigm is unscientific. An unscientific method inside a better paradigm is unscientific. A split on either layer is mixed. The worse layer decides.
1·Study methodology
Did this study test its claim with methods that are independent, falsifiable, and non-circular?
UNSCIENTIFIC
This study claims that certain bacterial proteins switch off the bacteria's defense against viruses by chopping up the alarm molecule that turns that defense on. All three tests fail.
Independently Verifiable
Fail
The gels showed bands and the mass spectrometer showed peaks, but the model told them those bands were a ring nuclease chopping up a signaling molecule.
Falsifiable
Fail
A null result would be blamed on wrong buffer or wrong temperature, never on the CRISPR model being wrong.
Non-Circular
Fail
The molecule they tracked was made by a CRISPR component and the protein was named by matching mass spec peaks against a database built from the same model.
Why
They grew archaeal cells, broke them open, and separated the contents through chemical columns. They tracked an activity by watching a radioactive band disappear on a gel. The radioactive molecule was made by mixing ATP with a protein complex the model calls Csm, which the model says produces a ring-shaped signaling molecule. They cut a protein band from a gel, chopped it with enzymes, and fed the pieces into a mass spectrometer. Software matched the peaks against a sequence database built from the genomic model and named the protein Sso2081. They cloned its gene using primers designed from the model's sequence, expressed the protein in bacteria, and showed it made the radioactive band change position on a gel. They called this a ring nuclease degrading a signaling molecule. Nobody saw a ring nuclease. They saw bands and peaks, and the model told them what those meant.
2·Paradigm · Molecular Biology / CRISPR Model
Does the framework this study assumes pass the three tests?
UNSCIENTIFIC
Independently Verifiable
Fail
Nobody has seen DNA inside a living cell, let alone watched a CRISPR system provide adaptive immunity.
Falsifiable
Fail
When a CRISPR experiment fails, the field blames the primers, the buffer, or the temperature, never the model itself.
Non-Circular
Fail
The sequencers, PCR machines, and mass spectrometers were all built from the DNA model they now claim to validate.
Why
The molecular biology framework assumes that DNA carries a code, that genes make proteins, and that those proteins do specific jobs inside cells. Nobody has seen DNA inside a living cell. Nobody has watched a gene produce a protein. Nobody has observed a CRISPR system fight off a virus. The instruments the field uses to study these things were designed using the same model they claim to confirm. A failed experiment is never blamed on the model. It is blamed on the primers, the buffer, the temperature, or the expression system. The model treats a band on a gel as a molecule doing a job rather than asking what the band actually is. The framework cannot die because every negative result has a technical explanation that leaves the premise untouched.
From the study
Each fraction was assayed for cyclic tetra-adenosine (cA4) degradation activity and fractions displaying cA4 degradation were pooled and concentrated
A protein band of ~18 kDa, the presence and abundance of which corresponded to a peak in cA4 degradation was excised, trypsin digested and identified by mass spectrometry.
This 'ring nuclease' is itself a protein of the CRISPR-associated Rossman-fold family, and has a metal-independent mechanism that cleaves cyclic tetraadenylate rings to generate linear diadenylate species and switches off the antiviral state.