A physical (electromagnetic) model of differentiation. 1. Basic considerations

There are a number of biological phenomena and events that cannot yet be adequately described, such as cell growth and differentiation, which may be controlled by physical factors. Fr?hlich (1980) has discussed the principles of dissipative structures as applied to electromagnetic interactions in relation to basic couplings in biological systems. Recently, increasing evidence of photon storage and ultraweak photon emission from living systems, particularly from DNA, has suggested the concept of an electromagnetic model of differentiation, based on the known quantum optical properties of nucleic acids. This model has the advantage over all ideas so far published, that it is (1) simple; (2) universally applicable to events in living matter, because it is consistent with both the quantum mechanical and the thermodynamic properties on the one hand, and the known biological and biochemical data and phenomena at the other hand; (3) it not only describes the phenomena and events in terms of pure mathematical parameters, but it can also explain them; and (4) it escapes the difficulty of finding basic control mechanisms, which themselves do not need a regulator, ad infinitum.     

Somatic polyploidy in extraembryonic membranes of the snake,Elaphe guttata

Summary Video-densitometric DNA measurements of Feulgenstained tissues of 42 day old eggs of the corn snake,Elaphe g. guttata (Columbridae, Serpentes), revealed a basic DNA content of 2C=2.17 pg, with somatic polyploidy in the allantois, the chorioallontois, the yolk sac, and other extraembryonic membranes. The maximum value determined was 128C (in binucleate cells 2×128C) at the distal pole of the egg. This is the first report of somatic polyploidy in a snake, and one of the first in reptiles in general.     

Karyological stability and microevolution of a cell suspension culture ofBrachycome dichromosomatica (Asteraceae)

A long-term suspension culture ofBrachycome dichromosomatica (2n = 4) was induced from a cotyledon-derived callus. Subcultures were obtained every week up to three years. The bulk of the cultures displayed a stable diploid karyotype, while one cell line evolved with 2n = 5 chromosomes in the 86th reinoculation. No further chromosomal change occurred also in that cell line. It is assumed that the fifth chromosome is the expression of a trisomy 2.The chromatin ultrastructure was of the species-specific chromomeric type in the wild-type line, while the trisomic line displayed more condensed chromatin, what probably indicates a rather inactive state of the extra-chromosome.Brachycome dichromosomatica is suggested to represent an ideal species to follow-up karyotype stability and/or variation in cell culture.As a former student W. N. dedicates this paper in gratitude and admiration to Prof. DrElisabeth Tschermak-Woess on the occasion of her 70th birthday. Prof.Woess with her scientific work has stimulated in an unique manner the study of nuclear structures in plants, of endopolyploidy and polytene chromosomes, and has thus established the basis for the rapidly increasing research in these fields.     

Light-stimulated ultraweak photon reemission of human amnion cells and Wish cells

Photon reemission in the ultraweak intensity range that is observed after irradiation of cell suspensions with light, reveals characteristic differences between normal human amnion cells and transformed Wish cells from the same parental tissue. The reemission kinetics, approximated best by a hyperbolical process, were studied as a function of cell density, showing that: malignant Wish cells have a photon storage capacity that is not improved by increasing the cell density; and that normal amnion cells exhibit a photon storage capacity that strongly increases with increasing cell density. The interpretation of this effect and the nature of the emitter are discussed.     

The course of the first meiotic prophase in Beta procumbens and in the F1 between B. vulgaris and B. procumbens

Summary The succession of the stages of the first meiotic prophase in Beta procumbens has been ascertained by measurements of the nuclear volume and by other criteria. By this method it has been possible to relate the appearance of pairing gaps to the beginning separation of the chromosomes after pachytene. A zygotene-like stage of early diplotene has been found. Asynchronous condensation of the bivalents and reduction of the chiasma frequency have been observed in diplotene and diakinesis. — The lengths and arm ratios of the pachytene chromosomes of Beta procumbens were determined.Stages similar to those in B. procumbens have been recognized in the F ₁ hybrid between Beta vulgaris and Beta procumbens. The pachytene chromosomes appeared to be paired to a great extent. However, only some of the cells showed bivalents in diakinesis, in the majority desynapsis occurred during diplotene or early diakinesis. In metaphase I, bivalents, univalents, cases of secondary association due to stickiness and cases of fragmentation have been observed.

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Zusammenfassung Die Stadienabfolge während der ersten meiotischen Prophase bei Beta procumbens wurde auf Grund verschiedener Kriterien, vor allem durch Messungen des Kernvolumens, bestimmt. Dadurch konnte das Auftreten von Paarungslücken auf die post-pachytänische Trennung der Chromosomen zurückgeführt werden. Während des frühen Diplotäns wurde ein Zygotän-ähnliches Stadium gefunden. Asynchrone Kondensation der Bivalente und Reduzierung der Chiasmenzahl wurden im Diplotän und in der Diakinese beobachtet. — Die Längen- und Armlängen-Verhältnisse der Pachytän-Chromosomen von Beta procumbens wurden bestimmt.Die gleichen Stadien wie bei Beta procumbens traten auch in der F ₁-Hybride zwischen B. vulgaris und B. procumbens auf. Die Pachytän-Chromosomen lagen offenbar weitgehend im gepaarten Zustand vor. Dennoch besaß in der Diakinese nur ein Teil der Zellen Bivalente, im größeren Teil der Zellen erfolgte während des Diplotäns oder der frühen Diakinese Desynapsis. In der Metaphase I wurden Bivalente, Univalente, Fälle von sekundärer Assoziierung (infolge stickiness) sowie Fälle von Chromosomen-Fragmentierung beobachtet.

     

Über den unterschiedlichen Formwechsel des Heterochromatins in der mitotischen Prophase vonLithospermum undLilium

Zusammenfassung In den Zellkernen vonLithospermum purpurocaeruleum setzt die mitotische Prophase so wie bei anderen Arten unter Zerstäubung der Chromozentren ein; an ihre Stelle treten Heterochromomeren, die sich im Höhepunkt an die umgebenden Euchromomeren angleichen. Später, wenn die Spiralisation der Chromosomen beginnt, zeigt sich wieder ein deutlicher Unterschied zwischen Eu- und Heterochromatin. Er bleibt kontinuierlich bis in die späte Prophase erhalten; erst dann erreichen die euchromatischen Teile der Chromosomen den gleichen Kontraktionszustand wie die heterochromatischen.BeiLilium henryi verläuft die Prophase anders. Im Zerstäubungsstadium wird zwar ebenfalls eine Zerlegung der interphasischen Chromozentren herbeigeführt, doch bleiben im gesamten weiteren Verlauf der Prophase eu- und heterochromatische Chromosomenteile völlig aneinander angeglichen.Die statistische Verteilung der Volumina der interphasischen und prophasischen Kerne spricht für die Zugehörigkeit des Zerstäubungsstadiums zur Prophase und gegen die Auffassung, daß es einem Teil der S-Periode zuzurechnen ist.

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In the nuclei ofLithospermum purpurocaeruleum mitotic prophase starts with the dispersion of the chromocenters, just as it does in other species, too; in place of the chromocenters heterochromomers come forth, which assimilate to the surrounding euchromomers at culmination time. Later, when the chromosomes begin to spiralize, a distinct differentiation in euchromatin and heterochromatin is visible again. It is conserved until late prophase. Only then the euchromatic parts of the chromosomes attain the same degree of spiralisation as the heterochromatic ones.InLilium henryi prophase takes another course. There is a decomposition of the interphase chromocenters in the dispersion stage, too, but during further prophase the euchromatic and heterochromatic parts of the chromosomes contract in the same way and are not differentiated from each other.The statistical distribution of the volumes of interphasic and prophasic nuclei confirms the assumption, that the dispersion stage belongs to prophase, and not to the S-period of interphase.

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Herrn Prof. Dr.Lothar Geitler, in Verehrung und Dankbarkeit zum 70. Geburtstag gewidmet.     

Growth-regulator Interactions in the Growth of the Shoot System of Avena sativa Seedlings: I. THE GROWTH OF THE FIRST INTERNODE

1. Segments, 3.5 mm. long, cut from the first internode of Avenasativa seedlings grown in complete darkness respond to bothauxins and gibberellic acid by accelerated extension. 2. The optimum concentration of indole-3-acetic acid (IAA) is10 p.p.m. and of gibberellic acid (GA) is 0.1 p.p.m. 3. The degree of stimulation relative to the growth of controlsegments is affected by the inclusion in the segement of thenode between the internode and coleoptile. Thus the gibberellineffect is greatly increased while the IAA effect is decreased.The optimal concentrations are not affected by inclusion ofthe node. 4. These results can best be explained in terms of the supplyby the node tissue of an endogenous auxin which is necessaryfor the expression of GA action. 5. Numerous factorial experiments demonstrated that there isno detectable interaction between applied IAA and GA in thepromotion of first-internode extension. This implies that thepostulated endogenous auxin which synergized GAA action in (4)is either an active form of IAA produced only in the node tissueor is a completely different auxin. 6. No synergism of growth-promotive action can be detected betweenGA and the two synthetic auxins I-naphthylacetic acid and 2,4-dichlorophenoxyaceticacid. 7. p-chlorophenoxy-iso-butyric acid (PCIB) anc 2,4,6-trichlorophenoxyaceticacid (2,4,6-T) act as weak auxins and thus antagonize competitivelythe promotive action of GA. 8. The anti-auxin -(I-naphythyl-methyl-sulphide)propionic acid(NMSP) antagonizes competitively the promotive action of bothIAA and GA. 9. The facts under (5)–(8) suggest that auxins and GAare acting at the same growth-promotion centres and may competefor them. 10. Growth inhibitions are induced by high concentrations ofPCIB, 2,4,6-T and NMSP. The inhibitions produced by PCIB and2,4,6-T are both synergized by supra-optimal concentrationsof IAA while that of NMSP is synergized by supra-optimal concentrationsof both IAA and GA. This similarity of the effects of IAA andGA suggests that their inhibition actions also are of a closelysimilar nature.     

Karyologische Anatomie der Samenanlage vonPinus silvestris

Zusammenfassung In der Samenanlage vonPinus silvestris zeigen das Volumen und die Struktur der Ruhekerne sowie die Größe und Form der Metaphasechromosomen nicht nur gewebespezifische Unterschiede, sondern auch eine große Variabilität in Abhängigkeit von der Lage innerhalb ein und desselben Gewebes und vom Entwicklungsstadium. Große Kerne können lockerer gebaut sein als kleine, aber auch ungefähr gleich dicht, manchmal sogar dichter; aus den großen, dicht gebauten gehen in der Mitose Chromosomen hervor, die ein vielfaches Volumen von denen aus kleinen Kernen aufweisen (bis 132).Im Makrosporen-Tapetum treten normale und gehemmte Mitosen nebeneinander auf, in deren Folge mehrkernige Zellen bzw. Restitutionskerne mit teilweise aneuploiden Chromosomenzahlen entstehen. Der Gesamtpolyploidiegrad einer Tapetumzelle beträgt maximal 16n.     

Cytidine Analogues and Stomatogenic Recovery in Amicronucleate Paramecium tetraurelia and Paramecium jenningsi

Removal of the micronuclei of Paramecium tetraurelia and Paramecium jenningsi by micropipetting generates amicronucleate cell lines. These cell lines go through a period of growth depression for several dozen fissions, but they gradually recover. Amicronucleate cells in the depression period characteristically exhibit abnormal oral development, particularly reduction in the length of the buccal cavity and an abnormal pattern of the oral membranelles. To test the notion that the macronucleus is involved in the recovery of amicronucleate cell lines, DNA demethylation drugs were administered to amicronucleates in the depression period. After at least 4 fissions, the treated amicronucleates were assessed for their progress in recovery by scoring the proportion of cells with normal oral membranelles. Cvtidine analogues which demethylate cytosine specifically at the 5 position, namely 5-azacytidine, 5-aza-2'- deoxycytidine and 5-fluoro-2'-deoxycytidine. promoted recovery of the amicronucleates. Cytidine, 6-azacytidine, 2'-fluoro-2'-deoxy-cytidine and cytosine-β-D-arabinofuranoside did not. These results suggest that (i) 5-methylcytosine is present in the macronucleus of these Paramecium species, probably in small amounts and (ii) recovery of amicronucleates involves demethylation of macronuclear DNA. This implies that in normal cells the micronuclei are involved in maintaining the macronuclear DNA in a methylated state and hence the inactivation of the macronuclear sequences that are to be employed for stomatogenic recovery. A general mechanism for the control of gene expression may therefore be employed for the regulation of specific sequences.     

Restriction fragment length polymorphisms of the phytohemagglutinin genes inPhaseolus andVigna (Leguminosae)

Restriction fragment length polymorphisms at the phytohemagglutinin (PHA) locus were determined among 21 genotypes ofPhaseolus vulgaris, P. coccineus, P. acutifolius, P. lunatus, and threeVigna species, using five restriction enzymes and one double digestion, in order to provide molecular evidence for their genetic relatedness. The dissimilarity between genotypes was estimated from binary RFLP data. The dissimilarity was high among species (from 0.75 to 0.95), and of variable extent among genotypes of the same species (0.33–0.89). InP. vulgaris, two different DNA hybridization patterns were found, giving further evidence for two major gene pools in that species. The restriction patterns ofP. vulgaris var.aborigineus, the putative ancestral form ofP. vulgaris, exhibit clear homology toP. vulgaris genotypes. An undefined landrace from Taiwan could be identified as aP. vulgaris genotype. RFLP-based trees for the phytohemagglutinin genes of the species studied were computed with several distance matrix and parsimony methods.