There are gaps in the science literature regarding how the human body
derives methyl mercury from inorganic dental mercury.
After much searching, I've come up with no references that would indicate
human metabolic processes perform this mercury transformation. One does
find that methyl cobalamin (methyl B12) will spontaneously react with inorganic
mercury creating a methyl mercury compound. This reaction occurs just by
having the two molecules in solution in a petri dish.
Plenty of evidence exists to show human demethylization and the creation
of mercury proteins. There is data to show mercury binding into all kinds
of human molecular structures causing disruption.
Metabolic conversion to free form methyl mercury by humans or mammals
cannot be substantiated in the literature. One reference I found, and included
on another page, addresses this explicitly.
So how does the mercury get to be methyl mercury in the human starting
from dental amalgam ? Dental amalgam irrefutably contains only inorganic
mercury. Another agent must be at work. Microorganisms in the mouth and
GI track gut quickly come under suspicion.
Behold, the gut does contain micro flora with this capability. Yeast,
strep, staff and E. coli all perform the transformation, it's referenced
here, it's proven.
Strep and staff are 100% pathogenic. Your health has near zero tolerance
for these organisms, though they often maintain a limited presence outside
the cell linings of the gut. It is very unlikely these pathogens contribute
to a long term mercury conversion process. Infections of these organisms
are generally acute in nature.
Yeast and E. coli are the two most compelling organisms to suspect since
both are usually not pathogenic, often behave symbiotically, and are known
to live in most guts.The ability to transform dental mercury to methyl mercury
is already living within the mouth and GI track of everyone who has a mercury
Read on for medical and scientific journal references that substantiate
"Transformations of inorganic mercury by Candida albicans and
Saccharomyces cerevisiae"; Applied and Environmental Microbiology,
Jan 1991; 57:1:245-247; S Yannai; I Berdicevsky, L Duek; Dept. of Food Engineering
and biotechnology, and Unit of Microbiology, Faculty of Medicine, Technion-Israel
Institute of Technology
"Saccharomyces cerevisiae and Candida albicans were incubated with
0.25, 0.5, or 0.75 ug of Hg (as HgCl2) per ml of Nelson's medium in the
presence of trace amounts of oxygen at 28 °C for 12 days. Two controlled
media were used, one without add Hg and one with out yeast inoculum. Yeast
cell growth was estimated after 1, 2, 3, and 8 days of incubation. The contents
of organomercury in the system and of elemental mercury released from the
media and collected in traps were determined at the end of the experiments.
The results were as follows. (i) C. albicans was the more mercury-resistant
species, but both yeast species failed to grow in the media containing 0.75
ug per ml. (ii) (iii) The amounts of organomercury produced by the two species
were proportional to the amount of HgCl2 added to the medium. In all cases
C. albicans produced considerably larger amounts of elemental Hg produced
were all similar in the case of C. albicans. (iv) Neither organomercury
nor elemental Hg was produced in any of the control media."
Experiment and Findings
1. Anerobic fermentation process, closed system with outlet only.
2. 14 day fermentation period.
2. Culture flask and fermentation effluent traps.
3. In the Candida albicans flasks, 0.9%-1% of the original mercury/ml was
free as organomercury.
4. In the traps 9-10% of the original mercury/ml was free as organomercury.
5. There was not a full accounting of original mercury: how much in yeast
? how much still in original species ?
6. Authors believe the organomercury was methyl mercury, they are certain
it was a carbon bearing compound.
"Speciation of methyl mercury and Hg(II) using bakers yeast biomass
(Saccharomyces cerevisiae) determination by continuous flow mercury cold
vapor generation atomic absorption spectrometry"; Anal. Chem.;
1995; 67:750-754; Y Madrid, Ca Cabrera, T Perez-Corona, C Camara; Departmento
de Quimica analitica, Facultad de Quimicas, Universidad Complutense, 28040
"Bakers yeast cells (Saccharomyces cerevisiae) were successfully used
to selectively separate methyl mercury and Hg(II). Several parameters affecting
the degree of biosorption and the binding kinetics of methyl mercury and
Hg(II) were evaluated: solution pH; temperature,incubation time, amount
of biomass and analyte, and presence of foreign ions. methyl mercury is
immediately bound to the yeast cells over a wide pH and temperature range.
The fraction of methyl mercury bound was in all cases 100% and was unaffected
by the parameters mentioned above. Hg(II) has less affinity for yeast cells
and remains in solution, although the percentage of Hg(II) bound to the
cell mass does increase at high incubation time (3 hours) and biomass. Of
the foreign ions tested, chloride at high concentrations strongly increases
the Hg(II) binding efficiency. methyl mercury and Hg(II) are quantitatively
separated under optimum conditions, i.e. 30 minutes incubation time at pH
7.0 and 37 °C. The results were compared with those obtained using a
S. cerevisiae isolate, and no significant differences were observed. Our
work suggests that the cell rapidly reduces CH3Hg+ to more volatile species
such as Hg(I) or Hg0, whereas Hg2+ is slowly bound and reduced, perhaps
because of the different toxicities of the two species. The method was applied
to the selective determination of Ch3Hg+ and Hg(II) spiked water samples.
In all cases good recoveries were obtained."
"The cell membrane is one of the major barriers along the toxicological
pathways of hazardous substances. Consequently, living cell systems can
be used as an analytical tool for trace analysis.
Various microorganisms are capable of binding dissolved metals in a variety
of environments. Microbes, composed mainly of polysaccharides, proteins,
and lipids, offer particularly abundant metal-binding functional groups.
Other biological processes that can occur include methylization, demthylization,
and reduction. These properties can be used not only for removing heavy
metal ions from polluted environments but also for differentiating species
according to their toxicity. although living organisms have been widely
used to preconcentrate metal ions, there have been few attempts to apply
this kind of substrate to metal speciation. Neidhart et al. used human red
blood cells for specific sampling of chromate even at high levels of Cr(III).
Mercury is a toxic metal whose toxicity depends on its chemical form. methyl
mercury is more toxic tha Hg2+, not only for humans but also for microorganisms.
Microorganisms (bacterias, yeasts, and other fungi) mediate three transformations
of mercury: they reduce Hg(II) to Hg0, they break down methyl mercury (and
other organomercury compounds), and they methylate Hg(II). Hg(II) is also
reduced and methylated by chemical reactions in the environment other than
those mediated by microorganism. This paper discusses the potential of the
yeast cell for the speciation of methyl mercury and Hg(II). The effects
of Ph, temperature, incubation time, mercury and yeast concentration, and
interferences from other metals are examined."
"Sub-cellular Location of Mercury in Yeast Grown in the Presence
of Mercuric Chloride"; Journal of General Microbiology; 1975; 86:66-74;
AD Murray; DK Kidby; Dept. of Microbiology, College of Biological Science,
University of Guelph, Guelph, Ontario, Canada.
"The distribution of 203Hg in Saccharomyces cerevisiae grown in the
presence of mercuric chloride has been examined by physical and chemical
fractionation procedures and autoradiography. The major fraction of the
bound mercury is tightly bound to the wall. A significant quantity of mercury
penetrates to the cytoplasm but only a minor fraction is present as low
molecular weight compounds. The wall associated mercury is not readily released
by extraction with sodium hydroxide or ethylenediamine but a major fraction
is solubilized by Pronase and Helicase treatment. Isolated walls are capable
of binding their own weight of mercury to high affinity adsorption sites.
The major role of the cell envelope in the in vivo binding of mercury
and the penetration to the cytoplasm of mercury was confirmed by autoradiography."
"Growth of yeasts is inhibited by most heavy metals which have been
examined (White & Munns, 1951). Of the group comprising cadmium, lead
and mercury, the last has been extensively characterized as an inhibitor
of enzymes due to it's number of functional groups (Vallee & Ulmer,
1972). The extracellular B-glucosidase and B-fructosidase of yeast have
been shown to be extremely sensitive to mercury (Mealor & Townshend,
1968; Kaplan & Tacreiter, 1966). However, despite the well documented
phenomenom of mercury inhibition of yeast, at both the moleular and cell
level, there has been no investigation of the distribution of mercury within
the cell. We attempted to define the distribution of mercury within the
cell. We attempted to define the distribution of mercury in growing yeasts
and to indicate the general nature of the mercury binding sites."
Experiment and Findings
1. aerobic vs anaerobic conditions not specified, growth medium was liquid.
2. Incubation time was 15 hours.
3. Nearly all the mercury present was in the yeast cells, with almost none
left in growth medium.
4. Major fraction of mercury was bound into the cell walls, only a small
proportion of this appeared to be in weakly bound ion exchange positions.
5. Yeast walls are capable of binding approximately their own weight of
"The methylization of mercuric chloride by human intestinal bacteria";
Experentia, 31:9; 1975; Sept 15, 1064-5; IR Rowland; P Grasso; MJ Davies;
British Industrial Biological Research Association, Woodmansterne Road,
Cashalton, Surrey, SM5 4DS, England.
"Most strains of staphylococci, steptococci, yeasts and E. coli isolated
from human feces, could synthesize methyl mercury compounds. In contrast,
few strains of obligate anerobes could do so. Up to 6 ng methyl mercury/ml
were formed in 44 hours from 2 ug / ml mercuric chloride."
Experiment and Findings
1. Except for lactobacillus and bifido-bacteria, all cultures incubated
in aerobic conditions.
2. Streptococci had highest methylization rate, followed by Staph, and E.
coli, then yeast.
3. Very few strains of GI friendly bacteria methylized. Those that did,
produced extremely little.
"Tissue content of mercury in rats given methylmeruric chloride
orally: influence of intestinal flora."; Arch Environ Health; 35:3,
1980 May-June; 155-60; IR Rowland; MJ Davies; JG Evans; British Industrial
Biological Research Association, Woodmansterne Road, Cashalton, Surrey,
SM5 4DS, England.
"The effect of intestinal flora on the absorption and disposition of
mercury in tissues was investigated using conventional rats and rats treated
with antibiotics to eliminate their gut flora.
Antibiotic treated rats given 203Hg labeled methylmercuric chloride orally
had significantly more mercury in their tissues, especially in kidney, brain,
lung, blood, and skeletal muscle, and also excreted less mercury in the
feces than conventional rats. Furthermore, in the kidneys of the antibiotic
treated rats, the proportion of mercury present as organic mercury was greater
than in the kidneys of the conventional rats. The results support the hypothesis
that the metabolism of methylmercuric chloride by the gut flora reduces
the tissue content of mercury. When rats were administered 10 mg methylmercuric
chloride/kg per day for 6 days, four of five of those given antibiotics
developed neurological symptoms of toxicity, whereas only only one of five
conventional rats given methylmercuric chloride was affected."
Facts and Findings
1. Inorganic Hg compounds are absorbed very slowly in the mammalian intestine
2. Alkyl-mercurial (carbon bearing mercury ) compounds are rapidly and completely
absorbed from the GI.
3. Rat feces were found to be free of bacteria after 3 days of the antibiotic
4. After 30 days four of five rates given antibiotic treatment developed
signs of severe methyl mercury chloride (CH3HgCl) poisoning.
5. Only 1 of five conventional rates developed severe CH3HgCl poisoning
in the same period.
6. Intestinal microflora reduce the severity of damage to the granular layer
of the cerebellum
7. Intestinal flora play a protective role by effectively reducing the toxicity
of ingested CH3HgCl.
"Microbial transformations of metals"; Annu Rev Microbiol,
32:1978, 637-72; AO Summers; Dept. of Microbiology, University of Georgia,
Athens, GA 30602
"Biological Methylation of Mercury...
Three alternative pathways for mercury metabolism have been proposed. (a)
bacteria living in bottom sediment and sludge can carry out mercury methylation
by excreting methylcobalamin, which serves as a methyl donor in vitro. Indeed,
bottom dwelling bacteria, soil anerobes, and yeasts, have been shown to
have the ability to methylate mercury....
(b) Second the mercury may be methylated by the normal bacterial flora of
the gills and guts of the fish...
(c) The third alternative for methyl mercury production is totally abiotic,
without the intervention of microbes or microbial metabolites..."
"Formation of methyl mercury by bacteria"; Appl Microbiol;
30:3, 1975; Sept; 424-32; MK Hamdy; OR Noyes; Dept. of Food Science, University
of Georgia, Athens, GA 30602.
"Twenty three Hg2+ resistant cultures were isolated from sediment of
the Savannah River in Georgia; of these, 14 were gram-negative shirt rods
belonging to the Genera Escherichia and Enterobacter, six were gram positive
cocci (three Staphylococcus sp. and three Streptococcus sp.) and three were
bacillus sp. All the Escherichia, Enterobacter, and the bacillus strain
were more resistant to Hg2+ that the strains of staphylococci and streptococci.
Adaptation using serial dilutions and concentration gradient agar plate
techniques showed that it was possible to select a Hg2+ resistant strain
from a parent culture identified as enterobacter aerogenes. this culture
resisted 1,200 ug of Hg2+ per ml of medium and produced methylmercury from
HgCl2, but was unable to convert Hg2+ to volatile elemental mercury (Hg0).
Under constant aeration (i.e., submerged culture), slightly more methylmercury
was formed than in the absence of aeration. Production of methylmercury
was cyclic in nature and slightly decreased if DL-homocysteine was present
in the media, but increased with methylcobalamine. Is is concluded that
the bacterial production of methyl mercury may be a means of resistance
and detoxification against mercurial in which inorganic Hg2+ is converted
to organic form and secreted into the environment."
"Effect of DL-homocysteine. Homocysteine was added in equimolar amounts
to that of Hg2+ (0.25 umol of Hg2+ per ml of media) present in GBSB and
the medium was then incubated aerobically. The results showed the absence
of MM, as detected by TLC or GLC, in the benzene extract of control medium.
It was also noted that the formation in the culture media after 3 and 20
days of incubation"
"Biotoxicity of Mercury as Influenced by Mercury(II) Speciation";
Applied and Environmental Microbiology, Oct. 1990, p. 3006-3016; RE
Farrell; JJ Germida; PM Huang; Department of Soil Science, University of
"Additions of cysteine at cysteine:Hg molar ratios greater than
1:10 to the M-IIY medium produced significant (P=0.01) increases in the
IC50 to the extent that Hg toxicity was virtually eliminated at a cysteine:Hg
molar ratio of 2:1."