Showing papers by "Max Planck Society published in 1971"

Selforganization of matter and the evolution of biological macromolecules

Abstract: IA. Cause and Effect . . . . . . . . . . . . . . 465 1.2. Prerequisites of Selforganization . . . . . . . 467 1.2.3. Evolut ion Must S ta r t f rom R andom Even ts 467 1.2.2. Ins t ruc t ion Requires In format ion . . . . 467 1.2.3. In format ion Originates or Gains Value by S e l e c t i o n . . . . . . . . . . . . . . . 469 1.2.4. Selection Occurs wi th Special Substances under Special Conditions . . . . . . . . 470

Two Fast Transient Current Components during Voltage Clamp on Snail Neurons

Abstract: Voltage clamp currents from medium sized ganglion cells of Helix pomatia have a fast transient outward current component in addition to the usually observed inward and outward currents. This component is inactivated at normal resting potential. The current, which is carried by K+ ions, may surpass leakage currents by a factor of 100 after inactivation has been removed by hyperpolarizing conditioning pulses. Its kinetics are similar to those of the inward current, except that it has a longer time constant of inactivation. It has a threshold close to resting potential. This additional component is also present in giant cells, where however, it is less prominent. Pacemaker activity is controlled by this current. It was found that inward currents have a slow inactivating process in addition to a fast, Hodgkin-Huxley type inactivation. The time constants of the slow process are similar to those of slow outward current inactivation.

Role of -aminobutyric acid (GABA) in the extrapyramidal motor system. 2. Some evidence for the existence of a type of GABA-rich strio-nigral neurons.

Abstract: Interference with the neuronal connection between the substantia nigra and striatum of rat by hemitransection at the subthalamic level or lesion of left side of striatum by a simple suction method was studied in relation to the concentration of γ-aminobutyric acid (GABA) in both regions. Time interval studies, at two, six, and twelve days after hemitransection, showed that the GABA concentration in substantia nigra had markedly decreased, whereas only a slight change was shown on the striatum of the operated side. Destruction of the striatum by suction caused a significant fall of the GABA content in the ipsilateral side of substantia nigra. However, destruction of the frontal cortex alone did not cause any marked change in the GABA content of the substantia nigra. In addition, electron microscopic studies disclosed that within the synaptic organization of the substantia nigra approximately 20 % of the boutons contained elongated synaptic vesicles, and that, following coagulation of the striatum, some large axosomatic terminals containing elongated synaptic vesicles also underwent degeneration.

The movement of molecules across lipid membranes: A molecular theory

Abstract: The movement of molecules across membranes is discussed in terms of thermal fluctuations in the hydrocarbon chains of the membrane lipids. The thermal motion of the hydrocarbon chains results in the formation of conformational isomers, so-called kink-isomers of the hydrocarbon chains. “Kinks” may be pictured as mobile structural defects which represent small, mobile free volumes in the hydrocarbon phase of the membrane. The diffusion coefficient of kinks is calculated to be 10−5 cm2/sec; thus kinks diffusion is a fast process. Small molecules can enter into the free volumes of kinks and migrate across the membrane together with the kinks; thus kinks may be regarded as intrinsic carriers of lipid membranes. An expression is derived from this model for the flow of molecules through lipid membranes. The calculated value for the water permeability is compatible with measurements on lipid bilayers.

On the fine structure of the peripheral retina and lamina ganglionaris of the fly, Musca domestica

Abstract: The peripheral retina and lamina ganglionaris of Musca domestica have been investigated electronmicroscopically.

Human Circadian Rhythms in Continuous Darkness: Entrainment by Social Cues

Abstract: Three groups of two subjects each were kept in underground chambers, first for 4 days in an artificial light-dark cycle, and thereafter for 4 days in complete darkness. They lived on a rigorous time schedule. Physiological as well as psychological functions were measured at 3-hour intervals. There were no differences in the results between the two sections of the experiment. Social cues are sufficient to entrain human circadian rhythms, and absence of light has no immediate effect on the functions measured.

Regeneration of whole plants from isolated mesophyll protoplasts of tobacco

Abstract: (1963). [5] v. Sengbusch, R., in: Vortragsveranstaltung fiber neue Methoden der Fischzflchtung und -haltung. Hamburg: MPI f. KulturpflanzenzClchtung t 9 6 7 . [6~ Langhans, V. : NachrichtenbI. Fischzucht Fischerei 1, 122 (t928). [7] Krupauer, V.: Ryb~stvi H. 6, 85 (t963). [8] v. Sengbusch, R., Meske, Ch., Szablewski, W.: Experientia 21, 614 (1965). --. [9] v. Sengbusch, R., et al.: Z. Fiscberei 15 N. F., 45 (1967). [10]Meske, Ch.: Fischwirt 16, 309 (1966). [il~ I(oBmann, H.: ibid. 20, 255 ( 1 9 7 0 ) . ~t2~ SchS~perclaus, W.: Lehrbuch der Teichwirtschaft. Berlin-Hamburg: Paul Parey 1961. [13] Jancarik, A.: Z. Fischerei 12 N. t~'., 602 (1964). [t4~ Lflhr, B., in : Vortragsveranstaltung fiber neue Methoden der Fischzflchtung und -haltung. Hamburg: MPI f. t,~ulturpflanzenzflchtung 1 9 6 7 . [15~ Meske, Ch.: Fischwirt 18, 310 (t968). [t6] 3/Ieyer-Waarden, P. F., in: Der Aal. Hamburg: A. Keune 1 9 6 5 . [171 M~ller, H. : Dtsch. Fischerei-Z. 14, t (t967). r t81 Meske, Ch.: Arch. Fischereiwiss. 20, 26 (1969). [191 Suworow, I~.: Grundlagen der Ichthyologie. Moskau 1 9 4 8 . [20] Ihering, G.: Zool. Anz. 3 (t935). [2t] Gerbilski, H. L.: Vesti. Leningrad un.-ta Mr. (zitiert nach Woyn~rovich 1963). (t951). [22] Woyn~rovich, E.: Beitr. Gew/~sserforsch. 4, 210 ( 1 9 6 4 ) . [23] Meske, Ch., et al.: Theoret. Appl. Genetics 38, 47 ( t 9 6 8 ) . [24~ Kof3mann, H.: Zuchthygiene, im Druck. [25] Meske, Ch., Lflhr, B., Szablewski, \"vV.: Naturwissenschaften 54, 291 (1967). [26] v. Sengbusch, R., Meske, Ch.: Zflchter 37, 271 ( 1 9 6 7 ) . [27] KoBmann, H., Szablewski, W.: Fischwirt 21, 49 (1971): ~281 Denkschrift der DLG-Tierzuchtabteilung ( t 9 6 7 ) . [29] Meske, Ch. : Fischwirt 19, 244 (t969).

Preparation and Properties of Antisera against the Lipid‐A component of Bacterial Lipopolysaccharides

Abstract: The lipid-A component of lipopolysaccharides, when presented in a suitable form, acts as an immunogen in rabbits, giving rise to the production of circulating antibodies. Highest anti-lipid-A titers were obtained on immunization with acid-treated bacterial cells coated with lipid A. Anti-lipid-A activity of the immune sera could be assayed by passive hemolysis of lipid-A-sensitized erythrocytes in the presence of complement. On filtration of the immune globulins on Sephadex G-200, antibodies against lipid A were detected in the IgM and IgG fractions. Lipid A preparations derived from various Salmonella and one Echerichica coli strain exhibited strong serological cross reactions with anti-lipid-A antisera. Furthermore, lipid-A antiserum also cross-reacted with all lipopolysaccharides tested, although in some cases to a low degree. On the other hand, only 8 out of 13 antibacterial antisera interacted with lipid-A-coated red cells. Finally, it was found that anti-lipid-A antibodies are effective in sensitizing E. coli 0111 bacteria for intraperitoneal phagocytosis.

Role of -aminobutyric acid (GABA) in the extrapyramidal motor system. 1. Regional distribution of GABA in rabbit, rat, guinea pig and baboon CNS.

Abstract: The regional distribution of GABA in the CNS of rabbit (17 regions), rat (14 regions), guinea pig (12 regions) and baboon (11 regions) was determined by sensitive enzymatic and fluorometric assay. In all species studied a high concentration of GABA was found in substantia nigra (8.5–10.1 mmoles/kg) and pallidum (6.5–8.2 mmoles/kg). Fairly high amounts were found in hypothalamus, superior and inferior colliculi, nucleus oculomotorius and dentate nucleus. The GABA concentration in spinal cord (white matter) had the lowest value.

Significance of phospholipase a for prostaglandin formation

Abstract: I f p r o s t a g l a n d i n s have p h y s i o l o g i c a l f u n c t i o n s a s hormones o r t r a n s m i t t e r substances,mechanisms f o r v a r y i n g t h e i r release must e x i s t . Unl ike many o t h e r a g e n t s , p r o s t a g l a n d i n s do n o t appea r t o be s t o r e d i n s i g n i f i c a n t amounts i n t i s s u e s b u t form r a p i d l y when t h e t i s s u e s are e x c i s e d and a l lowed t o s t a n d b e f o r e e x t r a c t i o n ( E l i a s s o n , 1959; PaceAsciak & Wolfe, 1968;Vogt e t a l l 1969) . T h i s i n d i c a t e s t h a t t h e b i o s y n t h e s i s of p r o s t a g l a n d i n s i s r e l a t e d i n t i m a t e l y t o t h e i r release and a c t i o n under p h y s i o l o g i c a l c o n d i t i o n s , a n d t h a t e x p e r i m e n t a l l y induced or enhanced release may mean s t i m u l a t i o n of b i o s y n t h e s i s , r a t h e r t h a n opening of s t o r e s . I n f a c t , f o r m a t i o n o f p r o s t a g l a n d i n a f t e r p h y s i o l o g i c a l or pha rmaco log ica l s t i m u l a t i o n h a s been obse rved i n v a r i o u s o rgans ( R a m w e l l e t a l l 1 9 6 6 ; Coceani e t a l , 1967;Vogt & DistelkBtter,l967;Davies e t a l l 1 9 6 8 ; B a r t e l s e t a l l 1 9 7 0 ) . The q u e s t i o n a r i s e s as t o which i s t h e ra te l i m i t i n g s t e p of p r o s t a g l a n d i n fo rma t ion which can be a c t i v a t e d and t h u s c o n t r o l t h e l e v e l o f a c t i v e p r o s t a g l a n d i n s . S e v e r a l fac t s s u g g e s t t h a t phospho l ipase A may be a r e g u l a t i n g f a c t o r ( V o g t e t a1 ,1966) . T h i s enzyme would c l e a v e p o t e n t i a l p r e c u r s o r a c i d s from t i s s u e p h o s p h o l i p i d s , and by t h i s a c t i o n p r o v i d e s u b s t r a t e f o r c o n v e r s i o n t o p r o s t a g l a n d i n s . I n f a c t , p e r f u s i o n of gu inea p i g lung o r f r o g i n t e s t i n e w i t h phospho l ipase A l e a d s t o prompt appeara n c e of l a r g e amounts of p r o s t a g l a n d i n i n t h e p e r f u s a t e (Vogt e t a l , l 9 6 9 ; B a r t e l s e t a 1 , 1 9 7 0 ) . F u r t h e r , i n j e c t e d or i n f u s e d a r a c h i d o n i c a c i d a p o t e n t i a l p r e c u r s o r of PGE2 and PGF2, i s c o n v e r t e d t o p r o s t a g l a n d i n s d u r i n g v a s c u l a r p e r f u s i o n of f r o g i n t e s t i n e ( B a r t e 1 s e t a1 ,1970) . By u s i n g a r a c h i d o n i c a c i d it h a s been shown t h a t p r o s t a g l a n d i n o r i g i n a t e s from t h e i n f u s e d p r e c u r s o r and forms r a p i d l y (Kunze,1970) . These f i n d i n g s i n d i c a t e t h a t t h e c o n v e r t i n g enzyme system i s h i g h l y a c t i v e i n i n t a c t t i s s u e , l i m i t e d i n i t s e f f i c i e n c y by t h e amount of s u b s t r a t e a v a i l a b l e l a n d t h e y p o i n t t o phospho l ipase A as t h e t r i g g e r i n g enzyme.

Enzyme alterations and lipid storage in three variants of tay-sachs disease

Abstract: — In autopsy tissues of 12 cases of Tay-Sachs disease the N-acetyl-β-hexosamini-dase A and B activities were investigated using chromogenic and physiological substrates. In three cases of Tay-Sachs disease, classified as the variant O, the enzyme activities A and B were missing; in eight cases, classified as the variant B, the enzyme activity A was missing. In another case, both enzyme activities wcre shown to be enhanced in brain tissue (‘variant AB’), using a chromogenic substrate. The three enzymic variants showed different glycolipid storage patterns of Tay-Sachs-ganglioside (TSG) and its asialo residue, the trihexosylceramide (THC) in the nervous tissues. Additional storage of kidney globosidc was found in the visceral tissues of the O variant. A decrease of the non-accumulated lipids, especially of those characteristic for myelin, was observed. The quantitative lipid determinations were performed by means of a thin-layer densitometric micromethod (standard deviation 2–5 per cent). Evidence is presented that the different storage patterns result from the corresponding enzyme alterations in the three variants. An essential condition for this statement was the isolation of the storage compounds from Tay-Sachs tissues and their radioactive labelling by the addition of tritium to the double bond in their sphingosine moiety. In a previous investigation it was shown that enzyme A degrades the storage compounds TSG, THC and kidney globoside while enzyme B acts on THC and kidney globoside only. In agreement with this finding, a highly concentrated mixture of both enzymes from normal tissues hydrolyses the main storage compound, the Tay-Sachs-ganglioside. This hydrolysis was reduced when corresponding enzyme preparations from tissues of variants of Tay-Sachs disease (including variant AB) acted on TaySachs ganglioside. Some properties of the N-acetyl-β-D-hexosaminidases from normal and from pathological tissues were determined with chromogenic and physiological substrates. The relationship between the enzymes A and B is discussed.

Systems of Monomolecular Layers—Assembling and Physico‐Chemical Behavior

Abstract: Systems of monomolecular layers can form functional units having properties not exhibited by the individual layers. On UV irradiation, for example, an energy transfer takes place from a sensitizer (S) layer to an acceptor (A) layer and results in fluorescence of A. S and A may be cyanine dyes. Monomolecular layers can be manipulated in many ways and combined to construct novel systems; the energy transfer method can be used to establish whether the desired structure has in fact been produced. The monolayer assembling technique can also be used for the investigation of the deactivation of excited molecules; an interesting example is the spectral sensitization of the photographic process.

Interaction of Lipopolysaccharides and Lipid A with Complement

Abstract: A number of lipopolysaccharides derived from Salmonella and Escherichia coli S and R mutant strains were tested for toxicity and anticomplementary activity in the absence of added antiserum. Although all preparations were toxic, only a few exhibited high anticomplementary activity, while others proved to be of low or negligible activity. It was found that isolated lipid A from both active and inactive lipopolysaccharides was strongly anticomplementary as well as toxic, when made water-soluble with the aid of suitable carriers. Treatment of R form lipopoly-saccharide with Mg2+ or Ca2+ led to complete precipitation of the lipopolysaccharide with consequent loss of toxicity and anticomplementary activity. This treatment had practically no effect on the anticomplementary activity and toxicity of S form lipopolysaccharides. When lipopolysaccharide, after reaction with complement, was reisolated and purified, the resulting preparation was found to be non-toxic and of negligible anticomplementary activity. No detectable alterations in either the sugar or the fatty acid composition could be detected. The only significant change was the loss of solubility in water. Treatment of the reisolated lipopolysaccharide with EDTA completely restored solubility in water, toxicity, and anti-complementary activity.

Les phénomènes de pseudopupille dans l'œil composé deDrosophila

Abstract: In the compound eyes of the fruitflyDrosophila, the dioptric system of each ommatidium is able to form virtual images of the receptor terminals (rhabdomere tips) throughout the whole depth of the eye. It is shown (§ 3) that 3 characteristic superposition phenomena occur for images formed by distinct ommatidia (Figs. 3b and 5). The most remarkable superposition appears at the point where the optical axes of all ommatidia converge (center of curvature of the eye). At this level, highly magnified virtual and erect images of corresponding rhabdomeres are superimposed, giving rise to adeep pseudopupil (Fig. 9). Since in the ommatidia ofDrosophila the rhabdome shows a pattern of 7 distal endings (Fig. 8a), the resultingdeep pseudopupil consists of 7 light spots with a similar pattern (Figs. 8b, 7, 11). Conversely thedeep pseudopupil of compound eyes which have fused rhabdomes consists of a single light spot (Fig. 19). Such pseudopupils can be best observed either with antidromic or with orthodromic illumination of the eye, according to the specific transmission or reflection properties of the rhabdomes. Thedeep pseudopupil of Dipterans is not to be confused with thecorneal pseudopupil (Fig. 13 a) and especially not with thereduced corneal pseudopupil observed with a reduced aperture of the microscope (Fig. 13 b), in spite of the remarkable similarity of these phenomena regarding the asymmetry and the dimension of their pattern (comp. Figs. 7 and 13b). Thereduced corneal pseudopupil consists of 7 facets whereas thedeep pseudopupil consists of 7 virtual images of the receptor endings. From the results of Kirschfeld (1967), the appearance of areduced corneal pseudopupil like Fig. 13 b on the eye ofDrosophila proves that 7 receptors located in 7 neighbouring ommatidia look in the same direction in space (Fig. 14). The existence of such an optical arrangement favors the view that the eye ofDrosophila, like that ofMusca, belongs to the "neural superposition type". A comparative study between thedeep pseudopupil and thereduced corneal pseudopupil leads to the following geometric relation, which is specific of theDrosophila eye and probably of all compound eyes of the "neural superposition type": % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaSaaaeaaca% WGebaabaGaamyzaaaacqGH9aqpdaWcaaqaaiaadkfaaeaaceWGMbGb% auaaaaGaaiilaaaa!3B44! $$\frac{D}{e} = \frac{R}{{f'}},$$ , whereD is the diameter of a facet,e the distance between the centers of two neighbouring rhabdomere endings,R the radius of curvature of the eye, andf? the focal length (in air) of a corneal lens. Other types of pseudopupils, commonly appearing as dark spots in compound eyes, are explained on a basis similar to thedeep pseudopupil of Drosophila (§5). In fact, the dioptric system of an ommatidium can give virtual images not only of its distal receptor endings but of the whole intensity distribution (i.e. the whole "luminous structure") which is present in its internal focal plane. If this structure is simple, thedeep pseudopupil, resulting from superpositions of virtual images, is likewise simple (Figs. 16 and 17). If the "luminous structure" is complex, as for example in the eye of the butterflyVanessa (Fig. 18a schematized in Fig. 18c), then thedeep pseudopupil shows the same complexity (Fig. 18 b and d). In compound eyes which lack screening pigment between their crystalline cones, one can seesecondary pupils of the 1st and 2nd order as described by Exner. Again they may be explained by superpositions of virtual images in the depth of the eye, according to Fig. 20. Moreover, thedeep pseudopupil of the "optical superposition eye" may be due to the fact that the more distal converging system of an ommatidium forms virtual images not of the rhabdome endings themselves but of real images of these endings (Fig. 21). Although the phenomenon of thedeep pseudopupil is not perceived by the animal, it is of interest for the experimenter who can use it: 1) to study the light receptors easily in the eye of live and intact animals, 2) to measure the physiological divergence angle between adjoining ommatidia, 3) to study the movement of the visual axis and the retinomotor adaptation of the receptors, and 4) to stimulate simultaneously manycorresponding receptors belonging to different ommatidia. The advantages of thisin vivo technique are discussed in § 6.3.

Separation of Receptor and Lamina Potentials in the Electroretinogram of Normal and Mutant Drosophila

Abstract: 1. In Drosophila the retinula cells and the cells in the lamina ganglionaris contribute to the ERG. This is due to extracellular resistance barriers across these cells ; one of these is situated near the proximal ends of the rhabdomeres separating the retinula cell layer from the rest of the fly, the other is situated either within several layers or homogeneously distributed throughout the lamina. Because of their different origin, two components of the ERG, the receptor potential and the lamina potential can be separated experimentally. 2. At high light intensity the receptor potential is larger than the lamina potential. However, under stimulus conditions where the receptor potential is very small ( a ) at low light intensity, ( b ) at high intensity but low flash contrast (Δ I / I ), ( c ) at high frequency of stimulation, the lamina potential exceeds the receptor potential. It is suggested that these properties reflect summation and adaptation of the sensory input within the lamina. The shape of the lamina potential has, under these conditions, the characteristics of a high-pass filter and may improve the fly9s response to high stimulus frequencies. 3. The ERGS of the mutants ebony, tan and opm 2 have normal or nearly normal receptor potentials but at the same time demonstrate severe defects in the lamina potentials. In ebony a fast on-effect at high intensity, and in tan a delayed off-effect at high intensity, are still present. The mutant opm 2 shows very little lamina activity at all. The difference of the defects in the three mutants argues against non-specific current leaks in or around the lamina. Therefore it is most likely that the lamina properties of summation, adaptation, and high-pass filtering, are largely lost in the three mutants. This is supported by behavioural experiments.

Association of viral reverse transcriptase with an enzyme degrading the RNA moiety of RNA-DNA hybrids.

Abstract: DURING replication of RNA tumour viruses, the genetic information contained in the viral RNA seems to be transferred to DNA1,2. Studies on the enzymatic activities present in the virus particles suggest that this transfer is mediated by an RNA dependent DNA polymerase3,4. RNA-DNA hybrids have been demonstrated to occur as intermediates in this reaction5 and single stranded DNA is generated as an early reaction product6, which is then replicated to give a double stranded DNA product6–8. The mechanism by which the single stranded DNA is displaced from the RNA template is, however, not known.

Duftunterscheidung bei der Honigbiene — Einzelzell-Ableitungen und Verhaltensreaktionen

Abstract: Einzelzellableitungen 1. Die Reaktionen einzelner Riechzellen der Porenplatten (Sensilla placodea) auf den Antennen der Honigbiene werden mit elektrophysiologischen Methoden untersucht. 2. Eine Methode wird beschrieben, die es erlaubt, gleichzeitig registrierte Implse verschiedener Zellen zuverlassig zu unterscheiden („stufenweise Adaptation“; Abb. 2 und 3). 3. Die Einzelzellableitungen von Drohnen, Arbeiterinnen und Koniginnen ergeben keine grundsatzlichen Unterschiede. 4. Die Riechzellen lassen sich mindestens sieben Reaktionsgruppen zuordnen, die jeweils auf ein bestimmtes „Spektrum“ von Substanzen (Reaktionsspektrum) antworten (Tabelle 1). Die Spektren der einzelnen Gruppen uberlappen sich nicht oder nur sehr geringfugig. Die Kennlinienfelder der Zellen einer Reaktionsgruppe weichen meist erheblich voneinander ab (Abb. 5). 5. Nach diesen Befunden last sich die bisherige Einteilung dieser Zellen in „Generalisten“ und „Spezialisten“ nicht mehr halten. Da auch Ergebnisse anderer Autoren sich mit diesem Einteilungsprinzip nicht in Einklang bringen lassen, werden neue Definitionen fur Generalisten und Spezialisten vorgeschlagen.

Phasenumwandlungen in Lipiden Mögliche Schaltprozesse in biologischen Membranen

Abstract: Recent experiments on phase transitions of lipid model membranes in aqueous medium are reviewed: the phase transition has been studied by optical methods using flourescence or absorption indicators and the kinetics of the transition by means of the temperature jump relaxation technique. Under certain conditions the transition curves show hysteresis phenomena. The ion binding and ion exchange properties of lipid structures are influenced by the phase transition. These phenomena may be important in memory and nerve excitation processes.