4. Discussion
One reason why the cyclooctaoxygen sodium-bridged spermine phosphate epigenetic shell of in vivo DNA was overlooked until now should be its destruction during DNA purification by the classical phenol extraction method of
Schuster,
Schramm &
Zillig [
57]. This original phenol extraction, although variously modified for nowadays use [
58], consistently precipitates the spermine as sperminediium (terminal NH
3+) di(phenolate) at pH 7.9–8.0 [
58], since the p
Ka value of phenol is 9.97 [potentiometric titration in H
2O,
ϑ = 25 °C, ionic strength (NaCl) 0.1] [
59], and the four p
Ka values of spermine are: p
Ka1 = 10.86 (terminal [
60] NH
3+), p
Ka2 = 10.05 (terminal NH
3+), p
Ka3 = 8.82 (inner [
60] NH
2+), p
Ka4 = 7.95 (inner NH
2+) [potentiometric titration in H
2O,
ϑ = 25 °C, ionic strength (NaCl) 0.1] [
38]. The cyclo-O
8-Na
+ could react with alkaline (pH 7.9–8.0) buffered phenol [
58] to disodium rhodizonate (C
6Na
2O
6), a known oxidation product of
p-benzoquinone, which in turn is an oxidation product of phenol. Regardless of the chemical details, the commercial salmon sperm DNA (utilized in [
5]) and calf thymus DNA preparations are devoid of cyclo-O
8-Na
+ and spermine phosphate complexation, since the methods utilized for calf thymus and salmon sperm sodium deoxyribonucleate preparation [treatment with sodium dodecyl sulfate, high salt (NaCl) treatment, repeated ethanol precipitation] certainly remove the cyclooctaoxygen sodium-bridged spermine phosphate epigenetic shell.
Our findings have important consequences for the epigenetics [
61] of eukaryotic in vivo DNA.
Kesel et al. suggested [
5] a model for a first epigenetic shell of in vivo DNA (
Figure 8), based on the observed complexation of cyclo-O
8-Na
+ and spermine phosphate to ssDNA. In this model [
5] the phosphate backbone of ssDNA binds one cyclo-O
8-Na
+ pro three nucleotides, and this binary complex binds one spermine monophosphate to form a ternary epigenetic core of DNA. The monohydrogen phosphate bridges the cyclo-O
8-Na
+ with the sperminium cation, and the cyclo-O
8-Na
+ has an inverted alternating orientation [
5]. Interestingly, the sperminium tetracation cannot bind alone to DNA in this model, since the distances [
d (
N1,
N4) = 490 pm;
d (
N4,
N9) = 620 pm;
d (
N1,
N12) = 1,600 pm] between the four ammonium nitrogens do not fit the intrastrand phosphate–phosphate distance of dsDNA (B-DNA:
dØ = 700 pm [
62,
63]; A-DNA:
dØ = 590–600 pm [
63,
64,
65,
66]; Z-DNA:
dØ = 590 pm (step pCp),
dØ = 600 pm (step pGp) [
66]). Therefore, it is quite remarkable that in this model for the first epigenetic shell of in vivo DNA [
5] a repeating unit is formed from cyclo-O
8-Na
+ and spermine phosphate that perfectly fits both the triplet nature of the genetic code [
67] and the repeating distance of the phosphate anion backbone of DNA.
In view of the important findings of
Kirmes et al. [
4], that an interaction of eukaryotic chromatin DNA structure with atmospheric oxygen partial pressure takes place, previous postulations [
5] have to be defined more precisely. Since, under switching to hypoxic conditions eukaryotic cell chromatin gets highly condensed [
4], accompanied by redistribution of the polyamine pool to the nucleus [
4], the cyclooctaoxygen sodium-bridged spermine phosphate epigenetic shell can only be restricted to actively transcribed gene regions of eukaryotic ‘open’ euchromatin, excluding occupation of condensed chromatin. Hypoxia should largely prevent metabolic formation of cyclooctaoxygen. Both under hypoxic conditions and in the metaphase of mitosis, where spermine synthesis is highest [
68], coincident with an extraordinary high condensation grade (15,000–20,000-fold) of metaphase chromatin [
69], none cyclooctaoxygen should be involved in covering the highly condensed chromatin DNA. Here no discrimination between eu- and heterochromatin is made in metaphase, and all mitotic eukaryotic chromatin DNA is complexed with spermine tetracation and spermidine trication (and, at small proportions, with putrescine and cadaverine dications).
In summary, this reflects the high mitotic chromatin condensation grade and is confirming the results with hypoxia-induced chromatin condensation under coinciding polyamine pool nuclear translocation [
4]. Interestingly, spermine and spermidine induced B-DNA to Z-DNA transition at epigenetic, non-5-methylated CpG island hotspots of prokaryotic plasmid DNA (pBR322 derivative) [
70], but, in contrast, stabilized and condensed prokaryotic chromosomal B-DNA [
71]. Z-DNA was found to be formed at CpG island transcriptional hotspots [
72,
73]. Regions near the transcription start site frequently contain sequence motifs favorable to form Z-DNA, and formation of Z-DNA near the promoter region stimulates transcription [
73]. All these observations point to the correctness of the model that the cyclooctaoxygen sodium-bridged spermine phosphate epigenetic shell is restricted to actively transcribed ‘hot spot’ gene regions of eukaryotic ‘open’ euchromatin. Importantly, this epigenetic shell of eukaryotic ‘open’ euchromatin covers each strand of dsDNA separately, one at the positive strand, one at the negative strand (double occupation), whereas the highly condensed dsDNA structures bind one polyamine molecule directly at the double strand (single occupation) [
18,
19,
20,
21,
39]. This is substantiated by the precise calculation of the apparent acid dissociation constant of the human genome DNA.
Kesel et al. also elaborated a model for selenium (as hydrogen selenite, HSeO
3–, at physiological pH 7.4) protection of DNA [
5]. Selenium, the element of the moon [
74], was discovered by
Jöns Jacob Berzelius (1779–1848) in 1817 and was named by him in honor of the Greek goddess of the moon
Selene (σελήνη) [
75]. Selenium is essential to mammalian physiology at nutritional levels, but supraphysiological intake of selenium is known to be toxic for mammals [
5,
8]. Sodium selenite (Na
2SeO
3), as hydrogen selenite HSeO
3– at pH 7.0 (selenious acid H
2SeO
3: p
Ka1 = 2.62, p
Ka2 = 8.32 [
76]), binds to calf thymus genomic B-DNA at pH 7.0 [
77], and to
Saccharomyces cerevisiae A-RNA at pH 7.0 [
78]. Selenium has the ability to protect DNA from noxious influences (oxidative stress, radiation, cytotoxic agents) [
5], and is essential to genomic stability [
5,
8,
79,
80], but the exact molecular biological basis for these phenomena is unknown. If in our model of a first epigenetic shell of in vivo DNA [
5] the monohydrogen phosphate is replaced by hydrogen selenite, an epigenetic explanation for the interaction of selenium with eukaryotic in vivo DNA could be given.
A coinciding correlation was obtained when the hydrogen selenite substitution content of the cyclooctaoxygen sodium-bridged sperminium hydrogen phosphate protection shell of human euchromatin was calculated from the optimal human blood serum level for the essential human micronutrient selenium (see
Section 2.5.). The optimal human blood serum level of selenium (as Se), given as 110 µg/l (ng/ml) from literature [
26,
27], coincided with the calculated optimal selenium human blood serum level, 107 µg/l (ng/ml), required to cover all ATG triplet codons in human euchromatin mRNA genes, both at the mRNA gene translation initiation triplet ATG codon and the 5′-UTR uORFs upstream start codons (uATGs transcribed to uAUGs). 49% of human mRNA genes contain at least one uATG start codon in their 5′-UTR [
29] [the downstream 3′-untranslated region (3′-UTR) contains none ATG start codon]. The median number of aa-coding triplets required for one triplet to be covered with the sperminium hydrogen selenite/cyclo-O
8-Na
+ complex in interphase euchromatin (in form of hydrogen selenite HSeO
3−) at the published [
26,
27] optimal human blood serum level of selenium [as Se, 110 µg/l (ng/ml)] was calculated as to be 560.44 aa. This result correlated well with the calculated number of aa triplets (576.40) required for the covering of all ATG triplet codons in human interphase euchromatin mRNA genes by one hydrogen selenite HSeO
3− molecule (within the sperminium hydrogen selenite/cyclo-O
8-Na
+ complex) at the calculated optimal human blood serum level of selenium [as Se, 107 µg/l (ng/ml)]. A model of the postulated [
5] first epigenetic shell of euchromatic in vivo DNA was deduced, as exemplified for a single-stranded hexanucleotide d(ApCpCpApTpGp), part of the transcribed and translated human gene open reading frame initiation codon ATG encoded in the
Kozak consensus sequence [
31] (
Figure 6). This model accounts for, at least some of, the well-known bimodal, protective and toxic, in vivo effects exerted by selenium onto mammalian physiology. A complete specific substitution pattern of hydrogen selenite for monohydrogen phosphate at ATG open reading frame initiation codons would be essential for eukaryotic gene regulation, but if the displacement ratio HSeO
3–/HPO
42– exceeds a certain physiological tolerance level, and hydrogen selenite is randomly incorporated into the eukaryotic protection shell of human euchromatin, the epigenetic equilibrium should collapse. The high, both acute and chronic, mammalian toxicity of sodium selenite (Na
2SeO
3) [
81] should be due, at least in part, to direct detrimental effects of supraphysiological levels of hydrogen selenite HSeO
3– on mammalian chromosomal DNA integrity and regulation of genome expression.
Assuming an essential biological function for the cyclooctaoxygen sodium-bridged spermine phosphate and selenite epigenetic shell, it was searched for substances able to
selectively destroy this epigenetic protection structure, and the total herbicide glyphosate,
N-(phosphonomethyl)glycine (ROUNDUP®, Monsanto), and its major environmental metabolite (aminomethyl)phosphonic acid (AMPA) [
82] were tested on the cyclo-O
8-Na
+ complex contained in
RC. Glyphosate was chosen because it represents the top selling total herbicide worldwide [
83], and
RC was selected because of its highest molar cyclo-O
8-Na
+ content in the complex series
NC,
dNC, and
RC [
5]. Glyphosate and AMPA show chemical properties which might predispose them for destruction of cyclooctaoxygen in general. Glyphosate and AMPA are very hydrophilic and amphoteric, and their phosphonate moieties could be suitable to interact with cyclo-O
8-Na
+. It was unequivocally shown that glyphosate and AMPA indeed
selectively destroy the cyclo-O
8-Na
+ complex contained in
RC (
Figure 3,
Figure 4 and
Figure 7). I therefore conclude that glyphosate and the major environmental glyphosate metabolite AMPA [
82] also destroy the cyclooctaoxygen sodium-bridged spermine phosphate and selenite epigenetic shell of human euchromatin, because destruction of cyclooctaoxygen is sufficient to bring this essential protection shield of human euchromatin into collateral epigenetic collapse.
To get support for the selectivity of AMPA as an epigenetic poison, the affinity of AMPA towards human mitochondrial γ-aminobutyric acid transaminase (ABAT) [
41], and to wild-type human liver peroxisomal alanine:glyoxylate aminotransferase (AGT) [
56], was determined. ABAT represents also a β-alanine transaminase [
41], and both enzymes were selected because of the structural similarity between AMPA and β-alanine/L-alanine. AMPA showed essentially no affinity to ABAT, but was very showly catabolized by AGT (
Figure 5A). This latter result is of interest, since the product of the half-transamination of AMPA by AGT is phosphonoformaldehyde (
Figure 5B) which can be oxidized (peroxisomal glycolate oxidase, cytoplasmic lactate dehydrogenase [
84]) to phosphonoformic acid (phosphonoformate, foscarnet) (
Figure 5B). Foscarnet represents a well-known inhibitor of mammalian [
85,
86] and viral [
85,
86] DNA-dependent DNA polymerases. Eukaryotic DNA polymerase α is crucially involved in chromosome maintenance, DNA repair and recombination, transcriptional silencing, checkpoint activation, and telomere length maintenance [
87]. Mammalian DNA polymerase α is potently inhibited by foscarnet [
85,
86]. Therefore, the low-affinity half-transamination of AMPA by AGT, the rate-limiting step leading to foscarnet, could negatively influence human chromosome maintenance, DNA damage repair, and telomere length preservation, mediated by the AMPA catabolite foscarnet inhibition of DNA polymerase α. This enzymatic catabolism provides an additional, minor mechanism of destabilization and impairment of eukaryotic chromosomal DNA indirectly induced by the environmental glyphosate metabolite AMPA.
5. Conclusions
An improved and corrected molecular biological model is proposed for a first epigenetic shell of eukaryotic euchromatin (
Figure 9). This model incorporates an epigenetic explanation for the interactions of the essential micronutrient selenium (as selenite) with eukaryotic euchromatin (
Figure 6). The sperminium hydrogen phosphate/cyclooctaoxygen sodium complex was calculated to cover the actively transcribed regions (2.6%) of bovine lymphocyte interphase genome dsDNA (double occupation). The polyamine (spermine/spermidine ratio 1.17) coverage of HeLa S3 cell metaphase chromatin dsDNA was calculated as 93.4% (single occupation). In murine cryptal enterocytic mitotic (late anaphase/early telophase) chromatin the obtained in vivo value corresponds to complete genomic coverage (single occupation), and to comprehensive and extensive nuclear RNA coverage, by the spermine tetracation and spermidine trication (spermine/spermidine ratio 0.85). Because cyclooctaoxygen seems to be naturally absent in hypoxia-induced highly condensed chromatin [
4], a model [
88] is proposed for the cyclooctaoxygen sodium-bridged spermine phosphate (and selenite) epigenetic shell of actively transcribed gene regions in eukaryotic ‘open’ chromatin DNA (
Figure 9). Furthermore, a working model is tabulated in summary for the selective cell cycle-dependent epigenetic occupation of eukaryotic DNA (
Table 1).
What may be the evolutionary conserved biological significance, and human pathophysiological implication, of this selective epigenetic shell? Obviously, the selective cyclooctaoxygen sodium-bridged spermine phosphate (and selenite) epigenetic shell serves to discriminate euchromatin from heterochromatin (
Table 1). Interestingly, a supraphysiological concentration of selenite induces S−G
2/M cell cycle arrest, locked in interphase [
89], and inhibits DNA and RNA synthesis [
90], again pointing on a crucial determination of the optimally hydrogen selenite-marked ATG codons in eukaryotic DNA mRNA genes. Both a deficiency (not all ATG codons marked by HSeO
3−) and an excess (randomly distribution of HSeO
3−-marking in genome, no more restricted to only ATG codons) of selenium concentration as hydrogen selenite exerts detrimental effects on eukaryotic gene regulation and expression. This reflects the specific life-essential role of selenium in eukaryotic gene processing and maintenance, a long sought function of selenium in human nutritional physiology, previously defined as ‘mysterious’ essentiality of selenium for human life [
74,
89]. Furthermore, during transcription of actively transcribed gene regions in eukaryotic ‘open’ chromatin the double helix must be unwound by DNA helicases and the strands must be separated to enable access to DNA-dependent RNA polymerases I, II, and III. This creates intermediate DNA single-strand regions which are prone to chemical structure damage by multiple noxious impacts like reactive oxygen species (ROS), mutagens, and UV light. The selective cyclooctaoxygen sodium-bridged spermine phosphate (and selenite) epigenetic occupation of these sensitive single-stranded stretches could serve as an intrinsic protection against structural damage. This would be a logic explanation for the selective nature of the separate occupation of both DNA strands, consequently retained when strands are separated for transcription of mRNA. Also intriguing seem to be pH effects, since spermine is a strong base, and the major pH-related damage to DNA is depurination creating apurinic sites at low pH. The precisely calculated intranuclear micro-pH gain, obtained by sperminium hydrogen phosphate/cyclooctaoxygen sodium complexation of B-DNA individual strands (essentially the same as the intranuclear micro-pH gain for condensed B-DNA strand-overarchingly covered by sperminium tetracations) should protect against low pH-depurination creating apurinic DNA lesions leading to DNA single-strand breaks [
91]. In this context the formation of kinetin (
N6-furfuryl-9
H-adenine) from DNA is well known [
92]. It should be emphasized that kinetin is not contained in native mammalian DNA, contrary to misleading claims [
93,
94], but is formed only during DNA damage. A mechanism for the kinetin formation in, or from, DNA was proposed [
93,
94], but it seems not to be conclusive in chemical reason, since furfural does not react with the adenine 6-NH
2 group under condensation to a
Schiff base under in vivo conditions [
92]. I therefore propose a chemical mechanistic deduced logical scheme [
95,
96,
97,
98] for the generation of kinetin from DNA by proton catalysis (kinetin-generating “base flip”, KGBF) (
Figure 10), based on proton-catalysed depurination and subsequent inverted adenine 6-NH
2 N-glycosylation [
95,
96], in consequence leaving back a DNA single-strand break. It is proposed that the cyclooctaoxygen sodium-bridged spermine phosphate epigenetic shell protects ssDNA from low pH-induced depurination, including, in part, generation of kinetin by KGBF. It is therefore concluded that the sperminium hydrogen phosphate/cyclooctaoxygen sodium complex serves to protect ssDNA from nucleic acid-mediated intrinsic low intranuclear micro-pH-induced depurination, including KGBF, creating apurinic sites and concomitant DNA single-strand breaks at eukaryotic genome regions engaged in active transcription.
In conclusion, it is logically obvious that any chemical agent, biochemical precursor (selenium) deficiency, and/or physical circumstance compromising the sperminium hydrogen phosphate/selenite–cyclooctaoxygen sodium complexation will inevitably lead to a severe disturbation of eukaryotic genome integrity, to an increased mutation rate, and to genomic DNA single-strand breaks. This is, in part, proved by the
Snyder–
Robinson X-linked mental retardation syndrome [
5], characterized by a defect in spermine synthesis, leading to nearly complete loss of the polyamine spermine. Therefore, it was initiated a search for chemical agents selectively destroying the epigenetic shell of eukaryotic euchromatin. A candidate molecule was found, and, hence, it was defined as an ‘epigenetic poison’. The total herbicide glyphosate,
N-(phosphonomethyl)glycine (ROUNDUP®, Monsanto), and its major environmental metabolite (aminomethyl)phosphonic acid (AMPA) [
82] were found, rather unequivocally, to selectively destroy the cyclo-O
8-Na
+ complex contained in
RC. Glyphosate and AMPA came into focus because (i) glyphosate represents the top selling total herbicide worldwide [
83], (ii) their chemical structure (phosphonate + amine) and properties (strongly hydrophilic and acidic) seemed to enable them to interact with cyclooctaoxygen sodium, (iii) glyphosate and ROUNDUP® are suspected to damage DNA and cause cancer in humans [
99], and (iv) AMPA is already widely distributed in global ecosystems like (surface) water [
100].
I allow me to conclude on basis of my findings that glyphosate, ROUNDUP® and AMPA are major examples of slow-acting, insidious ‘epigenetic poisons’, (i) slowly eroding and detoriating human, animal and plant genomic integrity, (ii) rattening human, animal and plant inborne protection of hereditary information against mutation, and (iii) disturbing the processing of human, animal and plant genetic information by transcription. It is hence inevitable for me to define glyphosate, ROUNDUP® and AMPA as a significant threat for human, animal and plant genomic stability, especially for future human generations forced to live under the glyphosate-, ROUNDUP®- and AMPA-induced radiomimetic effects.
Figure 1.
Parts of the original publication [
1] from 1677 by
Antoni van Leeuwenhoek with the description of the first light microscopic observation of crystalline spermine phosphate in human semen. (A) The title page 1040. (B) Page 1042 with Figure A showing the characteristic crystalline shape [
2] of spermine × 2 H
3PO
4 × 6 H
2O [
2]. The last paragraph including Figure A is read in New Latin: “
Et sum prædicta materia paucillum temporis steterat, in ea observabantur trilaterales figuræ ab utraque parte in aculeum desinentes, quibusdam longitudo minutissimæ arenæ, aliquæ aliquantulum majores, ut Figure A. Prætera, adeo nitidæ ac pellucidæ, ac si crystallinæ fuissent.”. English transcription: “
And I mentioned the matter which stood for a short time, in which trilateral figures were observed from both sides ending in a sting, some in length of minute grains, some a little larger, as Figure A. Moreover, so sleek and translucent, as if it were crystalline.”.
Figure 1.
Parts of the original publication [
1] from 1677 by
Antoni van Leeuwenhoek with the description of the first light microscopic observation of crystalline spermine phosphate in human semen. (A) The title page 1040. (B) Page 1042 with Figure A showing the characteristic crystalline shape [
2] of spermine × 2 H
3PO
4 × 6 H
2O [
2]. The last paragraph including Figure A is read in New Latin: “
Et sum prædicta materia paucillum temporis steterat, in ea observabantur trilaterales figuræ ab utraque parte in aculeum desinentes, quibusdam longitudo minutissimæ arenæ, aliquæ aliquantulum majores, ut Figure A. Prætera, adeo nitidæ ac pellucidæ, ac si crystallinæ fuissent.”. English transcription: “
And I mentioned the matter which stood for a short time, in which trilateral figures were observed from both sides ending in a sting, some in length of minute grains, some a little larger, as Figure A. Moreover, so sleek and translucent, as if it were crystalline.”.
Figure 2.
The calculation of the apparent acid dissociation constant of the haploid human genome, and of the interphase intranuclear micro-pH [
46] values induced by human genome depending on its intrinsic epigenetic occupation status. (A) The calculation of the apparent (effective) p
K′
a,HG = 2.5601 (
ϑ = 25 °C) of the haploid human genome according to the method of
Katchalsky & Gillis [
33] and
Kuhn & Kuhn [
34] [p
K′
a,HG = apparent acid dissociation constant (
ϑ = 25 °C) of haploid
H. sapiens genome B-DNA double helix; p
Ka,R–OH = 1.29 = theoretical p
Ka (
ϑ = 25 °C) [
32] of one isolated internucleotide phosphodiester (R–OH) proton;
s = 1 = number of statistical subunits on thread molecule [
34];
j = 6 = number of spacing atoms (at least distance) in one dsDNA repeating unit [
34];
b = 0.334 × 10
-7 cm (0.334 ± 0.01 nm [
35]) = length rise in cm of one B-DNA repeating unit (helix rise/bp) in solution;
hν = end–to–end distance of dsDNA at half-neutralization;
h0 = end–to–end distance of dsDNA]. (B) The theoretical micro-pH [
46] values surrounding
H. sapiens haploid (and diploid) interphase euchromatin were calculated as the intranuclear micro-pH induced by human haploid (and diploid) genome treated as a weak acid, from pH
DNA, pH
spermine, and pH
shell, by applying the formula for pH induced by weak acids: pH = –log
10 (
Ka ×
ca)
0.5, or the formula for pH induced by weak bases: pH = –log
10 [(
Kw ×
Kb) × (
cb)
-1]
0.5 (
Ka, acid dissociation constant;
ca, concentration weak acid;
Kw, dissociation constant of water,
Kw = 10
-14 (
ϑ = 25 °C);
cb, concentration weak base). The single-stranded human genome intranuclear interphase concentration
cDNA was calculated as: [1 genome × (6.022140857 × 10
23 mol
-1)
-1] × (33.5268 fl)
-1 = 49.5282 pM. The intranuclear micro-pH was calculated by the law for the calculation of the solution pH induced by salts of weak acids with weak bases: pH
salt = 0.5 × (pH
acid + pH
base).
Figure 2.
The calculation of the apparent acid dissociation constant of the haploid human genome, and of the interphase intranuclear micro-pH [
46] values induced by human genome depending on its intrinsic epigenetic occupation status. (A) The calculation of the apparent (effective) p
K′
a,HG = 2.5601 (
ϑ = 25 °C) of the haploid human genome according to the method of
Katchalsky & Gillis [
33] and
Kuhn & Kuhn [
34] [p
K′
a,HG = apparent acid dissociation constant (
ϑ = 25 °C) of haploid
H. sapiens genome B-DNA double helix; p
Ka,R–OH = 1.29 = theoretical p
Ka (
ϑ = 25 °C) [
32] of one isolated internucleotide phosphodiester (R–OH) proton;
s = 1 = number of statistical subunits on thread molecule [
34];
j = 6 = number of spacing atoms (at least distance) in one dsDNA repeating unit [
34];
b = 0.334 × 10
-7 cm (0.334 ± 0.01 nm [
35]) = length rise in cm of one B-DNA repeating unit (helix rise/bp) in solution;
hν = end–to–end distance of dsDNA at half-neutralization;
h0 = end–to–end distance of dsDNA]. (B) The theoretical micro-pH [
46] values surrounding
H. sapiens haploid (and diploid) interphase euchromatin were calculated as the intranuclear micro-pH induced by human haploid (and diploid) genome treated as a weak acid, from pH
DNA, pH
spermine, and pH
shell, by applying the formula for pH induced by weak acids: pH = –log
10 (
Ka ×
ca)
0.5, or the formula for pH induced by weak bases: pH = –log
10 [(
Kw ×
Kb) × (
cb)
-1]
0.5 (
Ka, acid dissociation constant;
ca, concentration weak acid;
Kw, dissociation constant of water,
Kw = 10
-14 (
ϑ = 25 °C);
cb, concentration weak base). The single-stranded human genome intranuclear interphase concentration
cDNA was calculated as: [1 genome × (6.022140857 × 10
23 mol
-1)
-1] × (33.5268 fl)
-1 = 49.5282 pM. The intranuclear micro-pH was calculated by the law for the calculation of the solution pH induced by salts of weak acids with weak bases: pH
salt = 0.5 × (pH
acid + pH
base).
Figure 3.
Color assays for cyclo-O8-Na+ contained in RC, for the destruction of cyclo-O8-Na+ by the glyphosate metabolite (aminomethyl)phosphonic acid (AMPA) (left, 1–6), and for the potential reduction of elemental iodine by AMPA (right, A and B). Solutions (left, 1–6) were: KI (1), KI + starch (2), RC + KI (3), RC + KI + AMPA (4), RC + KI + starch (5), and RC + KI + starch + AMPA (6). The concentrations in solution were: RC, 16.95 mM (with cyclo-O8-Na+, 67.79 mM); KI, 156.63 mM; AMPA, 99.06 mM. The solutions were incubated at two room temperatures for prolonged time. Afterwards (left, bottom row), both RC + KI (3) and RC + KI + AMPA (4) were extracted with deuterated chloroform (bottom phase), and (left, bottom row ) both RC + KI + starch (5) and RC + KI + starch + AMPA (6) were treated with L-ascorbic acid. Legend: left, top row (1–6) = first photograph series; left, middle row (1–6) = second photograph series; left, bottom row (1–6) = third photograph series; right, top row (first photograph series): (A) AMPA (76.55 mM) + iodine (as I2, 78.80 mM), (B) iodine (as I2, 78.80 mM); right, bottom row (second photograph series): (A) AMPA (51.03 mM) + iodine (as I2, 52.53 mM), (B) iodine (as I2, 52.53 mM).
Figure 3.
Color assays for cyclo-O8-Na+ contained in RC, for the destruction of cyclo-O8-Na+ by the glyphosate metabolite (aminomethyl)phosphonic acid (AMPA) (left, 1–6), and for the potential reduction of elemental iodine by AMPA (right, A and B). Solutions (left, 1–6) were: KI (1), KI + starch (2), RC + KI (3), RC + KI + AMPA (4), RC + KI + starch (5), and RC + KI + starch + AMPA (6). The concentrations in solution were: RC, 16.95 mM (with cyclo-O8-Na+, 67.79 mM); KI, 156.63 mM; AMPA, 99.06 mM. The solutions were incubated at two room temperatures for prolonged time. Afterwards (left, bottom row), both RC + KI (3) and RC + KI + AMPA (4) were extracted with deuterated chloroform (bottom phase), and (left, bottom row ) both RC + KI + starch (5) and RC + KI + starch + AMPA (6) were treated with L-ascorbic acid. Legend: left, top row (1–6) = first photograph series; left, middle row (1–6) = second photograph series; left, bottom row (1–6) = third photograph series; right, top row (first photograph series): (A) AMPA (76.55 mM) + iodine (as I2, 78.80 mM), (B) iodine (as I2, 78.80 mM); right, bottom row (second photograph series): (A) AMPA (51.03 mM) + iodine (as I2, 52.53 mM), (B) iodine (as I2, 52.53 mM).
Figure 4.
Color assays for the destruction of cyclo-O8-Na+ contained in RC by glyphosate and ROUNDUP® GRAN (top, 1–5), for the potential reduction of elemental iodine by glyphosate and ROUNDUP® GRAN (bottom, A1, A2, and B), and for cyclo-O8-Na+ contained in NC (bottom, NC1 and NC2). Solutions (top, 1–5) were: RC + KI + starch (1), RC + KI + starch + glyphosate (free acid) (2), RC + KI + starch + ROUNDUP® GRAN (3), RC + KI + glyphosate (free acid) (4), and RC + KI + ROUNDUP® GRAN (5). The concentrations in solution were: RC, 16.95 mM (with cyclo-O8-Na+, 67.79 mM); KI, 171.69 mM; glyphosate, 100.55 mM; glyphosate-Na, 108.15 mM. The solutions were incubated at two room temperatures for prolonged time. Legend (bottom): (A1) glyphosate (free acid, 102.52 mM) + iodine (as I2, 98.50 mM), (A2) ROUNDUP® GRAN (glyphosate-Na, 102.77 mM) + iodine (as I2, 98.50 mM), (B) iodine (as I2, 98.50 mM), (NC1, NC2) NC (18.25 mM, with cyclo-O8-Na+, 18.25 mM) + KI (259.04 mM) after 10 h (NC1) and 50 h (NC2) incubation.
Figure 4.
Color assays for the destruction of cyclo-O8-Na+ contained in RC by glyphosate and ROUNDUP® GRAN (top, 1–5), for the potential reduction of elemental iodine by glyphosate and ROUNDUP® GRAN (bottom, A1, A2, and B), and for cyclo-O8-Na+ contained in NC (bottom, NC1 and NC2). Solutions (top, 1–5) were: RC + KI + starch (1), RC + KI + starch + glyphosate (free acid) (2), RC + KI + starch + ROUNDUP® GRAN (3), RC + KI + glyphosate (free acid) (4), and RC + KI + ROUNDUP® GRAN (5). The concentrations in solution were: RC, 16.95 mM (with cyclo-O8-Na+, 67.79 mM); KI, 171.69 mM; glyphosate, 100.55 mM; glyphosate-Na, 108.15 mM. The solutions were incubated at two room temperatures for prolonged time. Legend (bottom): (A1) glyphosate (free acid, 102.52 mM) + iodine (as I2, 98.50 mM), (A2) ROUNDUP® GRAN (glyphosate-Na, 102.77 mM) + iodine (as I2, 98.50 mM), (B) iodine (as I2, 98.50 mM), (NC1, NC2) NC (18.25 mM, with cyclo-O8-Na+, 18.25 mM) + KI (259.04 mM) after 10 h (NC1) and 50 h (NC2) incubation.
Figure 5.
The catabolism of AMPA by human peroxisomal alanine:glyoxylate aminotransferase (AGT). (A) Time course of the AMPA half-transamination reaction of human AGT. The enzyme at a concentration of 5 µM was incubated at
ϑ = 25 °C in 100 mM potassium phosphate buffer (pH 7.4). At the indicated times, aliquots were withdrawn and denatured. After removal of the precipitated protein by centrifugation, the supernatants were subjected to HPLC analysis (squares, PLP; circles, PMP). (B) The generation of phosphonoformate (foscarnet) from AMPA over the intermediate phosphonoformaldehyde by the rate-limiting transamination of the major environmental glyphosate metabolite AMPA. Phosphonoformaldehyde, seen as an glyoxylate analogue, could be oxidized by glycolate oxidase (GO) and lactate dehydrogenase (LDH) [
84]. Foscarnet is a potent inhibitor of eukaryotic DNA polymerase α [
85,
86], an enzyme crucially involved in maintaining chromosomal integrity and telomere length [
87].
Figure 5.
The catabolism of AMPA by human peroxisomal alanine:glyoxylate aminotransferase (AGT). (A) Time course of the AMPA half-transamination reaction of human AGT. The enzyme at a concentration of 5 µM was incubated at
ϑ = 25 °C in 100 mM potassium phosphate buffer (pH 7.4). At the indicated times, aliquots were withdrawn and denatured. After removal of the precipitated protein by centrifugation, the supernatants were subjected to HPLC analysis (squares, PLP; circles, PMP). (B) The generation of phosphonoformate (foscarnet) from AMPA over the intermediate phosphonoformaldehyde by the rate-limiting transamination of the major environmental glyphosate metabolite AMPA. Phosphonoformaldehyde, seen as an glyoxylate analogue, could be oxidized by glycolate oxidase (GO) and lactate dehydrogenase (LDH) [
84]. Foscarnet is a potent inhibitor of eukaryotic DNA polymerase α [
85,
86], an enzyme crucially involved in maintaining chromosomal integrity and telomere length [
87].
Figure 6.
Molecular modeling [ACD/Chem Sketch version 2022.1.0 with integrated ACD/3D Viewer (Advanced Chemistry Development, Inc., Toronto, Ontario, Canada), Mercury 2022.3.0 (The Cambridge Crystallographic Data Centre, Cambridge, United Kingdom)] of the postulated [
5] first epigenetic shell of euchromatic in vivo DNA, as exemplified for a single-stranded hexanucleotide d(ApCpCpApTpGp), part of the transcribed and translated human gene open reading frame initiation codon ATG encrypted in the
Kozak consensus sequence 5′-ACC
ATGG-3′ [
31], introducing a molecular biological model for sperminium hydrogen phosphate/cyclo-O
8-Na
+/ssDNA (left) and sperminium hydrogen selenite/cyclo-O
8-Na
+/ssDNA (right) interactions. Element color codings: grey, carbon; white, hydrogen; blue, nitrogen; red, oxygen; purple, phosphorus; green, sodium; yellow, selenium.
Figure 6.
Molecular modeling [ACD/Chem Sketch version 2022.1.0 with integrated ACD/3D Viewer (Advanced Chemistry Development, Inc., Toronto, Ontario, Canada), Mercury 2022.3.0 (The Cambridge Crystallographic Data Centre, Cambridge, United Kingdom)] of the postulated [
5] first epigenetic shell of euchromatic in vivo DNA, as exemplified for a single-stranded hexanucleotide d(ApCpCpApTpGp), part of the transcribed and translated human gene open reading frame initiation codon ATG encrypted in the
Kozak consensus sequence 5′-ACC
ATGG-3′ [
31], introducing a molecular biological model for sperminium hydrogen phosphate/cyclo-O
8-Na
+/ssDNA (left) and sperminium hydrogen selenite/cyclo-O
8-Na
+/ssDNA (right) interactions. Element color codings: grey, carbon; white, hydrogen; blue, nitrogen; red, oxygen; purple, phosphorus; green, sodium; yellow, selenium.
Figure 7.
Explanation of the color reaction for cyclo-O8-Na+ contained in RC, and the destruction of cyclo-O8-Na+ by the glyphosate metabolite (aminomethyl)phosphonic acid (AMPA). (A) The cyclo-O8-Na+ complex contained in RC reacted with potassium iodide under catalysis by potato starch to an intensely colored (reddish violet) [(cyclo-O8-Na+)2(I42–)] complex stabilized within the starch-contained amylose helix. (B) The proposed chemical formula for the amylose-complexed [(cyclo-O8-Na+)2(I42–)]: bis(octoxocane-κ4O1,O3,O5,O7)(μ-2λ3,3λ3-tetraioda-1,3-diene-κI1:κI4)disodium. (C) A logically deduced catalytic ‘rolling-circle’ mechanism for the AMPA-catalysed degradation of cyclo-O8-Na+. The cycloocytooxygen ring is split to a phosphonate-esterified nonaoxidanide which is stabilized by ionic binding to the primary ammonium cation of AMPA. The phosphonate-esterified nonaoxidanide eliminates four oxygen O2 molecules by a ‘rolling-circle’ cascade, regenerating AMPA.
Figure 7.
Explanation of the color reaction for cyclo-O8-Na+ contained in RC, and the destruction of cyclo-O8-Na+ by the glyphosate metabolite (aminomethyl)phosphonic acid (AMPA). (A) The cyclo-O8-Na+ complex contained in RC reacted with potassium iodide under catalysis by potato starch to an intensely colored (reddish violet) [(cyclo-O8-Na+)2(I42–)] complex stabilized within the starch-contained amylose helix. (B) The proposed chemical formula for the amylose-complexed [(cyclo-O8-Na+)2(I42–)]: bis(octoxocane-κ4O1,O3,O5,O7)(μ-2λ3,3λ3-tetraioda-1,3-diene-κI1:κI4)disodium. (C) A logically deduced catalytic ‘rolling-circle’ mechanism for the AMPA-catalysed degradation of cyclo-O8-Na+. The cycloocytooxygen ring is split to a phosphonate-esterified nonaoxidanide which is stabilized by ionic binding to the primary ammonium cation of AMPA. The phosphonate-esterified nonaoxidanide eliminates four oxygen O2 molecules by a ‘rolling-circle’ cascade, regenerating AMPA.
Figure 8.
A logically deduced catalytic ‘rolling-circle’ mechanism for the (fully ionized) glyphosate-catalysed degradation of cyclo-O8-Na+. The cycloocytooxygen ring is split to a phosphonate-esterified nonaoxidanide which is stabilized by ionic binding to the secondary ammonium cation of glyphosate (and complexation of the sodium cation). The phosphonate-esterified nonaoxidanide eliminates four oxygen O2 molecules by a ‘rolling-circle’ cascade, regenerating glyphosate.
Figure 8.
A logically deduced catalytic ‘rolling-circle’ mechanism for the (fully ionized) glyphosate-catalysed degradation of cyclo-O8-Na+. The cycloocytooxygen ring is split to a phosphonate-esterified nonaoxidanide which is stabilized by ionic binding to the secondary ammonium cation of glyphosate (and complexation of the sodium cation). The phosphonate-esterified nonaoxidanide eliminates four oxygen O2 molecules by a ‘rolling-circle’ cascade, regenerating glyphosate.
Figure 9.
An improved and corrected model for the cyclooctaoxygen sodium-bridged spermine phosphate (and selenite) epigenetic shell [
5] of actively transcribed gene regions in eukaryotic interphase ‘open’ chromatin DNA. (A) The nucleus of an eukaryotic cell with chromosome territories, chromatin fiber (10 nm ‘beads–on–a–string’ fiber), nucleosome structure, nucleosome octamer core histone proteins [H2A/H2B, H3/H3 variant, H4] with posttranslational histone protein modifications (histone PTM), and decondensing DNA with regulative cytosine nucleobase 5-methylation sites (me). Adapted and modified in part from [
88]. (B) The decondensation of chromatin enabling gene transcription in eukaryotic interphase ‘open’ chromatin DNA. The relaxed chromatin, regulatory transcription factor, chromatin-remodeling complex/histone acetyl transferases (HATs), and chromatin remodeling are indicated. The ‘open’ DNA with the transcription-prone gene is generally structured in promoter, promoter-proximal genetic elements, transcribed/expressed gene exons and non-expressed gene introns. The cyclooctaoxygen sodium-bridged spermine phosphate (and selenite) epigenetic coverage of this actively transcribed gene region is symbolized.
Figure 9.
An improved and corrected model for the cyclooctaoxygen sodium-bridged spermine phosphate (and selenite) epigenetic shell [
5] of actively transcribed gene regions in eukaryotic interphase ‘open’ chromatin DNA. (A) The nucleus of an eukaryotic cell with chromosome territories, chromatin fiber (10 nm ‘beads–on–a–string’ fiber), nucleosome structure, nucleosome octamer core histone proteins [H2A/H2B, H3/H3 variant, H4] with posttranslational histone protein modifications (histone PTM), and decondensing DNA with regulative cytosine nucleobase 5-methylation sites (me). Adapted and modified in part from [
88]. (B) The decondensation of chromatin enabling gene transcription in eukaryotic interphase ‘open’ chromatin DNA. The relaxed chromatin, regulatory transcription factor, chromatin-remodeling complex/histone acetyl transferases (HATs), and chromatin remodeling are indicated. The ‘open’ DNA with the transcription-prone gene is generally structured in promoter, promoter-proximal genetic elements, transcribed/expressed gene exons and non-expressed gene introns. The cyclooctaoxygen sodium-bridged spermine phosphate (and selenite) epigenetic coverage of this actively transcribed gene region is symbolized.
Figure 10.
A chemical mechanistic deduced logical scheme for the generation of kinetin (
N6-furfuryl-9
H-adenine) [
92] from DNA by proton catalysis (kinetin-generating “base flip”, KGBF). Protonation of the adenine nucleobase of the shown d(pAp
ApAp) sequence at purine N-7 induces depurination [
91], creating an apurinic site [
91]. Proton-catalysed
N-glycosylation [
95,
96] at the 6-NH
2 of adenine regenerates a nucleobase-inverted 2′-deoxynucleotide which is in furanose ring-opening equilibrium with its ald(os)imine form. Two eliminations simultaneously follow, the first (auto-catalysed by 3’-
O-phosphate conjugate base proton reception) by S
N2-nucleophilic eliminative epoxide formation, the second by proton-catalysed (auto-catalysed by the previously liberated 3’-
O-monohydrogen phosphate conjugate acid) β-elimination (E1 unimolecular elimination), which leads to an 3,4-epoxyolefin:
N-{(1
E,2
E)-3-[(2
S)-oxiran-2-yl]prop-2-en-1-ylidene}-9
H-purin-6-amine. The chiral (
S)-2-vinyloxirane structure rearranges to a chiral (
R)-2-alkyl-2,5-dihydrofuran due to 3,4-epoxyolefin rearrangement [
97,
98]:
N-[(2
R)-2,5-dihydrofuran-2-ylmethyl]-9
H-purin-6-amine. The latter compound rearranges to kinetin through facile double bond migration driven by aromatization to a furan. A DNA single-strand break is left back.
Figure 10.
A chemical mechanistic deduced logical scheme for the generation of kinetin (
N6-furfuryl-9
H-adenine) [
92] from DNA by proton catalysis (kinetin-generating “base flip”, KGBF). Protonation of the adenine nucleobase of the shown d(pAp
ApAp) sequence at purine N-7 induces depurination [
91], creating an apurinic site [
91]. Proton-catalysed
N-glycosylation [
95,
96] at the 6-NH
2 of adenine regenerates a nucleobase-inverted 2′-deoxynucleotide which is in furanose ring-opening equilibrium with its ald(os)imine form. Two eliminations simultaneously follow, the first (auto-catalysed by 3’-
O-phosphate conjugate base proton reception) by S
N2-nucleophilic eliminative epoxide formation, the second by proton-catalysed (auto-catalysed by the previously liberated 3’-
O-monohydrogen phosphate conjugate acid) β-elimination (E1 unimolecular elimination), which leads to an 3,4-epoxyolefin:
N-{(1
E,2
E)-3-[(2
S)-oxiran-2-yl]prop-2-en-1-ylidene}-9
H-purin-6-amine. The chiral (
S)-2-vinyloxirane structure rearranges to a chiral (
R)-2-alkyl-2,5-dihydrofuran due to 3,4-epoxyolefin rearrangement [
97,
98]:
N-[(2
R)-2,5-dihydrofuran-2-ylmethyl]-9
H-purin-6-amine. The latter compound rearranges to kinetin through facile double bond migration driven by aromatization to a furan. A DNA single-strand break is left back.
Table 1.
Tabulation of the selective cell cycle-dependent occupation of eukaryotic DNA by epigenetic polyamine shells. 1 ×, single quartet occupation (one polyamine pro both strands); 2 ×, double triplet occupation (one polyamine pro one strand); Chr, chromatin.
Table 1.
Tabulation of the selective cell cycle-dependent occupation of eukaryotic DNA by epigenetic polyamine shells. 1 ×, single quartet occupation (one polyamine pro both strands); 2 ×, double triplet occupation (one polyamine pro one strand); Chr, chromatin.
Cell cycle phase |
Heterochromatin |
Euchromatin |
Interphase |
Function (concise) |
Spermine-occupation? |
Cyclo-O8-Na+-occupation? |
Spermine-occupation? |
Cyclo-O8-Na+-occupation? |
G0 (Gap 0) |
Resting and quiescence |
No |
No |
Yes (2 ×) – With cyclo-O8-Na+
|
Yes (2 ×) – On ‘open’ Chr |
G1 (Gap 1) |
Transcription and histone synthesis |
No |
No |
Yes (2 ×) – With cyclo-O8-Na+
|
Yes (2 ×) – On ‘open’ Chr |
S (Synthesis) |
DNA synthesis |
No |
No |
Yes (2 ×) – With cyclo-O8-Na+
|
Yes (2 ×) – On ‘open’ Chr |
G2 (Gap 2) |
Translation |
No |
No |
Yes (2 ×) – With cyclo-O8-Na+
|
Yes (2 ×) – On ‘open’ Chr |
Mitosis |
Function (concise) |
Spermine-occupation? |
Cyclo-O8-Na+-occupation? |
Spermine-occupation? |
Cyclo-O8-Na+-occupation? |
Prophase |
Chr condenses into chromosomes, nucleolus disappears |
Yes (1 ×) – Condensing Chr |
No |
Yes (1 ×) – Condensing Chr |
No |
Prometaphase |
Kinetochore and polar microtubules attach, mitotic spindle formed, nucleus disappears |
Yes (1 ×) – Condensed Chr |
No |
Yes (1 ×) – Condensed Chr |
No |
Metaphase |
Centrosomes pull chromosomes, chromosome centromeres line up at metaphase plate |
Yes (1 ×) – Highly condensed Chr |
No |
Yes (1 ×) – Highly condensed Chr |
No |
Anaphase |
Chromosomes break at centromeres, sister chromatids separated by microtubules |
Yes (1 ×) – Maximally condensed Chr in late anaphase |
No |
Yes (1 ×) – Maximally condensed Chr in late anaphase |
No |
Telophase |
Chr reformed from chromosomes, nucleus and nucleolus reappear |
Yes (1 ×) – Maximally condensed Chr in early telophase |
No |
Yes (1 ×) – Maximally condensed Chr in early telophase |
No |