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On the nature of mitochondria. V. A critical analysis of Portier's Les symbiotes

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Resumen por el autor, I. E. Wallin.
Sobre la naturaleza de las mitocondrias
V. Un andisis critic0 de la obra de Portier “Les
Portier en 1918 ha llegado a una concepci6n bacterial de las
mitocondrias. Dicho autor cree que 10s “ symbiotes ” (niitocondrias) entran y salen del organism0 constantemente. Los
“ symbiotes ” son organismos omnipresentes que exhiben extrema
resistencia a 10s agentes fisicos y quimicos.
Translation by Jos6 F. Nonidez
Cornell Medical College, New York.
B Y T E E B I B L I O G R A P H I C S E R V I C E , J A N U A R Y 29
Department of Anatomy and the Henry S. Denison Research Laboratorips
University of Colorado School of MedicinP, Boulder, Colorado.
Since the publication of ‘‘ Die Elementarorganismen und ihre
Beziehungen zu den Zellen” in 1890 there have been only a
few expressions of opinion which have leaned towards Altmann ’s
conception of mitochondria. These expressions have been more
of the nature of opinions based on generalities than convictions
arrived at from experimental and observational evidence. The
major part of mitochondria1 literature, particularly that of
recent years, has attempted t o establish a cytoplasmic origin for
mitochondria. The success of this adventure may be measured
by the uncertainty and indifference with which this conception
has been received by biologists in general. It appears that the
basis for a conception of cytoplasmic origin of these structures
rests chiefly on topographical relationship. In its final analysis
such a basis carries no more proof of origin than may be found
in the old adage: “possession is nine points of the law.”
Portier’s ‘Les Symbiotes’ (’18) is, apparently the first pretentious experimental work which supports, in part, Altmann ’s
conception of mitochondria. While Portier ’s opinion differs
from Altmann’s conceptions in many particulars, the two opinions agree in the essential part of the hypothesis, namely, that
mitochondria are organisms of a bacterial nature. Independent
of Portier ’s researches and on the basis of experimental grounds
and evidence by analogy, the writer (Wallin 1922 a, b) has also
arrived at a bacterial conception of mitochondria. The writer’s
conceptions were arrived at from different lines of investigation
than those employed by Portier. His conceptions are also
quite different from Portier’s, especially in regard to the origin
of mitochondria.
Portier’s hypothesis may be better stated by quoting from
the preface of ‘Les Symbiotes’: ‘‘Chaque cellule vivante renferme
duns son protoplusme des formations que les histologists designenl
sous le nom de mitochondries. Ces organites ne seraient pour moi
autre chose que des bacteries symbiotiques, ce que j e nomme des
‘symbiotes’ . . . L a bacterie symbiotique vient d u milieu
exterieur: elle peut, duns certains cas, y retourner et vivre d ’une vie
independante. Les bacteries seraient donc les seuls etres simples;
tous les autres seraient doubles. ’’
The chief basis for Portier’s conclusions rests on his results
from attempts to grow mitochondria in artificial culture media.
The results innthese attempts have not been successful with all
tissues. The successful growths were obtained chiefly from the
fat in relation to the sex organs, particularly the testes. Attempts
at cultivating the mitochondria of the pancreas and liver, for
example, have been unsuccessful. This failure is accounted for
on the basis of his general theory regarding the nature and relationship of mitochondria. Portier believes that the ‘symbiotes ’ are especial microorganisms found in great abundance in
nature. They are constantly entering and leaving the host
organism under normal conditions. After entering a host they
first occupy an intercellular position and later take up an intracellular relationship. In the intercellular relationship the
organisms retain their hardy properties and are easily cultivated
in culture media. After the ‘symbiotes’ have taken up the intracellular position they lose their hardy qualities, develop fragility
and are quite incapable of cultivation in culture media.
A remarkable characteristic of Portier ’s ‘symbiotes’ is their
extraordinary resistance to chemical and physical agents. The
organisms after a number of passages in culture may be brought
to a moist temperature of 115” C. before they are destroyed.
I n a state of desiccation they resist temperatures up to 150’ C.
‘Symbiotes ’ in culture media resist the action of absolute alcohol
and chloroform for a period of a year. Further, the organisms
resist 5 per cent phenol for more than fifty hours, 20 per cent
formaldehyde for twenty five hours, and 10 per cent tincture of
iodine for twenty four bours. The organisms may be exposed
to the action of X-rays for considerable periods of time without
being destroyed.
The temperature at which the ‘syinbiotes’ were cultivated
varied with the source of the ‘symbiotes.’ The organisms from
higher vertebrates were best grown at a temperature of 40” C.
while those from invertebrates were cultivated at a temperature
of 25” C. In all the cultural experiments only one type of
organism was produced for each temperature group. The culture
media used were ordinary bacteriological media. The experiments were apparently conducted with particular precautions to
guard against contaminations. The room in which the work was
done was thoroughly scrubbed, the instruments used were sterilized in a flame and other general precautions were observed.
The cultural experiments were repeated a number of times with
constant results.
There is a great temptation to drift into fields of pure speculation when one is dealing with a problem of the nature of mitochondria. In a bacterial conception of these structures one
faces a myriad of possibilities in life processes and biological
relationships that suggest an entirely new and unique conception
of life. Altmann could not resist this temptation and his speculations led him into conflict with established facts in biology.
Portier discusses various functional relationships of ‘ symbiotes’
to the cell, both normal and pathological. While these speculations are interesting their significance is dependent upon the
determination of the nature of mitochondria.
The premises for Portier’s researches rest on a statement
attributed to Louis Pasteur in which he maint,ained that the
tissues of a healthy animal are free from bacteria. This statement
leads Portier to differentiate between the ‘interior medium’
which is aseptic and the ‘exterior medium’ which contains
numerous microorganisms. It is difficult to determine just
what Portier means by ‘interior’ and ‘exterior’ media. From
the content of his dissertation it appears that the ‘interior’
medium is an intercellular medium and the ‘exterior’ medium
refers to any position that is physiologically outside of the
body. Pasteur ’s statement concerning the aseptic condition of
the tissues of healthy animals is undoubtedly erroneous. Medical
literature in recent years contains a number of observations
which refute this statement. Gurney-Dixon (’20) claims to
have found bacteria present in 80 per cent of apparently healthy
animals. The writer’s experience in this direction does not
agree with Pasteur’s contention. I n a few attempts I have been
able to get luxuriant bacterial growth on the ordinary agar
culture media from lymph nodes of apparently healthy young
rabbits and kittens. While an attempt has not yet been made
to determine the relative prevalence of bacteria in the tissues of
apparently healthy animals, these preliminary experiments
point to a relatively high percentage of prevalence.
If bacteria are normally present in the tissues of apparently
healthy animals, it is obvious that the fundamental basis for
Portier ’s experiments is faulty. Portier made his cultures from
the tissues of adult animals. It is quite impossible to determine
whether he was dealing with intercellular symbiotic organisms
which are, apparently, normally present or if he actually produced
cultures from mitochondria.
It is difficult to harmonize Portier’s ‘symbiotes’ with the
known microorganisms. Their remarkable resistance to physical
and chemical agents would suggest a hitherto unknown type of
organism. Obviously, with such characteristics they are not
identical with mitochondria. That they are the extracellular
representatives of mitochondria remains to be demonstrated.
Such free living and hardy forms fit well into Portier ’s hypothesis.
However, there are certain conditions which Portier has not
taken into consideration, conditions which have a decided bearing
on the solution of the origin of mitochondria. Portier believes
that the ‘symbiotes’ are constantly entering the host organism
by way of the alimentary tract. This assumption is based on
various observations on the presence of bacteria in the intestinal
lumen and cells of insects and rabbits. In the rabbit he found
bacteria in the intestinal contents, and apparently the same
strain of bacteria within the epithelial cells of the intestine. The
writer has made the same observation on a one-day old kitten.
Portier further observed that some of the bacteria in the insect
intestinal epithelium were digested within the iell: Some of the
apparently ingested bacteria, however, he maintains are retained
intact within the cell. There is very little room for doubt concerning the ingestion of some bacteria by the intestinal epithelial
cells. However, there appears to be no relationship between this
phenomenon and the origin of mitochondria. While it is possible
that the intestinal tract may be the avenue of entry for ‘new
symbiotic complexes,’ the perpetuation of such a new symbiotic
complex is by way of the germ cell. The presence of mitochondria
in the germ cell has been demonstrated beyond a doubt. Their
increase by simple division in embryonic differentiation has
also been observed. The possibility of a functional and morphological differentiation in the developing host is supported by the
analogous conditions which are present in the differentiation of
the symbionts in the higher lichens.
Aside from his results in the cultural experiments in ‘symbiotes,’
Portier has brought forth a number of observations which support
a bacterial conception of mitochondria. A great portion of this
evidence deals with the relationship of bacteria to insect life.
These bacterial forms are not mitochondria. If they are ‘symbiotes ’ they strengthen Portier ’s hypothesis, but this remains
to be determined. However, in many instances they do furnish
examples of bacterial relationships to higher organisms which
are similar to the relationships of mitochondria to the cell.
It is quite certain that a definite transplantation of rnitochondria to an artificial culture medium would constitute
conclusive evidence of the organismal character of mitochondria.
The failure to accomplish such growth, however, is not evidence
of a cytoplasmic origin of mitochondria.
ALTMANN,R. 1890 Die Elementarorganismen und ihre Beziehungen zu den
Zellen. Leipzig.
GURNEY-DIXON1920 The transmutation of bacteria. Cambridge.
P. 1918 Les Symbiotes. Masson, Paris.
WALLIN,IVANE. 1922 a, On the nature of mitochondria. 1. Observations on
mitochondria staining methods applied to bacteria. 2. Reactions of
bacteria to chemical treatment. Am. Jour. Anat., vol. 30, no. 2.
1922 b, On the nature of mitochondria. 3. The demonstration of
mitochondria by bacteriological methods. 4. A comparative study of
the morphogenesis of root-nodule bacteria and chloroplasts. ilmer.
Jour. Anat., vol. 30, no. 4.
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nature, critical, symbiotes, analysis, les, portier, mitochondria
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