Showing papers in "Naturwissenschaften in 1980"

Synergetics: Are cooperative phenomena governed by universal principles?

Abstract: Synergetics is concerned with the cooperation of individual parts of a system that produces macroscopic spatial, temporal, or functional structures. The following article deals with an aspect of synergetics of particular interest: Are there general principles that govern the self-organized production of macroscopic structures irrespective of the nature of the individual parts? Unification of seemingly diverse phenomena and ideas under a general idea has been a main goal of science since ever. Be it philosophical approaches to construct a unique picture of the world, or, more specifically, theories belonging to individual sciences. In physics, well-known examples of such views arc Newton's theory of gravitation or Maxwell's theory of electromagnetism. A quite recent development has been the unification of theories of weak and electromagnetic interaction by Glashold, Salam and Weinberg. Further examples of physics out of many others are Einstein's unifying theory of space, time and matter. From other fields, we may quote Mendelejev's table of the chemical elements, or Mendel's laws of inheritance as classical examples. While this search for unifying ideas is still pursued, science itself splits into more and more disciplines each of which speaks its own language and uses its own methods. ]'he original attempt at unification seems to be more and more buried under a giant wave of new, more and more specialized results. In view of this it might seem absurd to search for any concepts capable to bring about new links between different fields of research. But this is exactly what synergetics* does. In this article I wish to describe some of its aims, its success and its limitations.

Flavonoids as larval growth inhibitors. Structural factors governing toxicity.

Abstract: Various flavonoid types are known to confer resistance toward insect attack in several plant species. Thus, a C-glycosyl flavone isolated from the silk of a resistant variety of maize was shown to inhibit the growth o fthe corn earworm,Helio this zea[ 1, 2], and O-glycosyl flavones and aglycones are significant factors against the development of Heliothis virescens, H. zea and Pectinophora gossypiella on cotton flower buds [3, 4]. Similarly, flavonoid tannins are implicated as insect resistance factors of the oak tree and of the cotton plant as well [5, 6]. However, the pentahydroxy flavone, morin, which occurs naturally in mulberry actually stimulates the consumption of artificial diets by silkworm moth larvae [7], and a glycosylated flavone has also been shown to be responsible for the feeding of Agasicles beetles on alligatorweed [8]. Up to now only a relatively small number of structural variants among the flavonoids has been examined by insect bioassay, and an interpretation of these structural features has not been forthcoming. In order to clarify this topic, we

False queens: a consequence of mandibular gland signals in worker honeybees.

Abstract: Observations on queenless honeybees have indicated that it is possible for workers to become egg layers [1-7]. What is even more curious is that some of these laying workers are capable of becoming what Sakagami has called "false queens" [3, 5]. The criteria for this designation being dependent on their ability to elicit retinue behaviour and in being able to inhibit emergency queen rearing in other workers should female larvae be available. Laying workers and false queens are both able to inhibit to some extent ovarial development in other workers. These behavioural and physiological effects can be understood in terms of the production of chemical signals a false queen emits which allow her to mimic queen signals [6]. The queen mandibular gland signals, within the hive, are involved in eliciting retinue behaviour and in the inhibition of both emergency queen rearing and ovarial activation in the workers [7]. The chemical constituents of this gland have been extensively investigated. The major component of the queen mandibular gland has been identified as (E)-9-oxo-2decenoic acid (9-ODA) [8, 9], the so-called queen substance. The worker mandibular gland produces (E)-10-hydroxy-2-decenoic acid (10-HDA), which is also a component of royal and worker jellies [t0] and 2-heptanone which is thought to be an alarm substance [tl, 12]. Recently a number of other fatty acid constituents have been identified in royal jelly and the mandibular glands of workers and queens [13]. Thus worker mandibular gland contents are said [14, 15] to differ markedly from those of the queen and hence the signals workers may be capable of releasing should be very different from those of the queen. The distinction between queen and worker signals has been blurred by the discovery that Apis mellifera capensis workers can synthesize the major component of the queen mandibular gland secretion, 9ODA, in their mandibular glands [16, 17]. Workers of A. capensis are capable of becoming laying workers very readily [1] and these workers, when placed in queenless groups of other races [16], very rapidly establish themselves as false queens. That these laying workers are capable of mimicking queen mandibular gland secretions and thus could produce queen-like chemical signals, destroyed the distinction [14, 18] that had previously been drawn between queen and worker mandibular gland products. As with ovarial development, the effects of caste determination on the biosynthetic capabilities of the mandibular gland are not irrevocable. The fact that A. capensis workers (amongst other pecularities) can become laying workers and false queens so readily, suggested that they occupied an intermediate position between A. melliJera workers and A. mellifera queens in terms of their ability to produce queen-like signals. However, the occasional appearance of false queens among A. mellifera laying workers [4, 7] was the spur which made us reinvestigate these mandibular gland signals. The mandibular glands of the series of honeybees (Table 1) were investigated by removing the pair of mandibular glands from each individual and analysing their contents gas-chromatographically (Fig. 1) [19, 20]. The bees used in these experiments were reared and maintained according to methods described in [5]. The A. mellifera workers in group A (Table 1), as has been reported previously [14, 15], have secretions dominated by 10HDA. This fatty acid is said to be "characteristic" of workers [18] yet is present in all the individuals examined. The two egglaying individuals produced a greater range of acids (10-HDA, 10-HDAA, 9HDA) than workers with underdeveloped ovaries with one exception. The exceptional individual with underdeveloped ovaries also produced a range of acids similar to that of the laying workers. The enhanced production of acids in this individual suggests that the production of appropriate mandibular gland signals may precede ovarial development. The secretions of the A. mellifera laying

The mode of action of the herbicide glyphosate

Abstract: 1. Blaschke, G.: Angew. Chem. 92, 14 (1980); Audebert, R. : J. Liqu. Cbromatogr. 2, 1063 (1979) 2. Lindner, W., et al. : J. Chromatogr. 185, 323 (1979) 3. Hare, P.E., Gil-Av, E.: Science 204, 1226 (1979); Gilon, C.,et al.: J. Am. Chem. Soc. 101, 7612 (1979); Gil-Av, E., Tishbee, A., Hare, P.E. : private Mitteilung (1979) 4. Davankov, V.A., Zolotarev, Y.A., Kurganov. A.A.: J. Liqu. Chromatogr. 2, 1191 (1979) ; Davankov, V.A., Zolotarev, Y.A. : J. Chromatogr. 155, 285, 295, 303 (1978) 5. Gfibitz, G., et al.: J. High Resol. Chromatogr. Chromatogr. Commun. 3, 145 (1979); Foucault, A., Caude, M., Oliveros, L.: J. Chromatogr. 185, 345 (1979) 6. Martell, A.E., Smith, R.M. : Critical Stability Constants. New York: Plenum Press 1974

Cell fusion induced by high electric impulses applied to Dictyostelium

Abstract: (of an individual egg) could be as short as the time needed for the doubling of the largest replicating unit (ap-prox. 4min, Fig. I c). Our finding that 14% of the molecules are in replication is fully compatible with both of these extreme possibilities. When cells of the eukaryotic microorganism Dictyostelium discoideum are repeatedly exposed to electric fields, they fuse into multinuclear, motile cells, the largest ones containing more than 40 nuclei. Under optimal conditions, i.e., initial field intensities of 4 to 6 kV/cm with decay times of about 40 ps, lysis of cells as a result of membrane permeabilization is negligible. This means that cells can be fused extensively without substantial loss. The apparatus used for generating high electric impulses of short duration has been described elsewhere [1]. Most of our experiments were carried out using the D. dis-coideum strain Ax-2, which is adapted to growth in liquid medium [2]. However, similar results were obtained with a wild-type strain, v-12/M2, grown in suspension on E. coil B/r as a nutrient. Impulses of the initial field intensity Eo decaying exponentially with time according to E(t) = Eo\" exp (-t/RC) were applied (R resistance of the cell suspension ; C ca-pacitance of the discharge circuit). Cells were suspended in 17 mM Soerensen phosphate buffer pH 6.0 at a density of 107 or 2.10 s cells/ml and, in the latter case, bubbled with oxygen before transferring 1-ml samples into a chamber equipped with two flat platinum electrodes separated by a distance d-1.4 cm. At the lower density the cells had to be agglutinated by rolling the suspensions in plastic tubes in order to produce maximal contact between the cells before subjecting them to field impulses. Agglutination strongly increased the yield of fused ceils. Repeated impulses given at intervals of 1 to 3 s were more efficient than single ones. Our standard procedure consisted of 3 or 4 impulses applied at intervals of 3 s. Celt fusion was found to have occurred as soon as the cells could be removed from the electrode chamber and put under a microscope , i.e., within the first few seconds after the repeated exposure to an electric field. MgC1 z or CaC12 at a concentration of 2 mM inhibited fusion when present during field application. Since the absence of divalent cations resulted in delayed lysis of the cells as manifested at about 0.5 h after field application, …

Hydrocarbons from plants: Analytical methods and observations

Abstract: We have suggested that certain plants rich in hydrocarbon-like materials might be cultivated for renewable photosynthetic products. Two species were selected for experimental plantations: Euphorbia lathyris, an annual from seed and Euphorbia tirucalli, a perennial from cuttings. The yield from each species is over 10 barrels of oil/acre/year without genetic or agronomic improvement. In addition to plants, there are trees, such as species of Copaifera in Brazil and other tropical areas, which produce a diesel-like oil upon tapping. Each tree produces approximately 40 liters of hydrocarbon per year, and this material can be used directly by a diesel-powered car. Further efforts to develop plants as alternate energy sources are underway, as well as a continuing search for additional plant species throughout the world which have a similar capability.

Calcium ions and pigment migration in fly photoreceptors.

Abstract: reached statistical significance. A Newman-Keuls analysis revealed that treatment with 5 mmol/l solutions of lithium chloride produced no significant effects on channel entry as compared with control treatment, but that 10 and 15 mmol/1 solutions significantly extended maximum entry distances. There was no significant difference between the 10 and 15 mmolfl treatments in this respect. These findings clearly indicate a dose-related effect of lithium chloride on channel entry by goldfish, an effect which is in line with previous findings that lithium salts impair responsiveness to environmental stimulation. Since in the present case it is likely that the drug effect was upon stimulation mediated by the lateral line system, it would appear that this aspect of lithium action is independent of sensory modality. There is no evidence from previous work on animals that lithium influences sense organ functioning, at least in the concentrations used in this experiment, and earlier work using fish suggests that the current findings cannot be explained as a result of impaired locomotory activity. The results of this study are therefore consistent with the hypothesis that lithium salts attenuate central stimulus analysis processes.

Metabolic microspheres: origins and evolution.

Abstract: A systematic review of catalytic activities in thermal proteinoids and microspheres aggregated therefrom yields some new inferences on the origins and evolution of metabolism. Experiments suggest that, instead of being inert, protocells were already biochemically and cytophysically competent. The emergence and refinement of metabolism ab initio is thus partly traced conceptually. When the principle of molecular self-instruction, as of amino acids in peptide synthesis, is taken into account as a concomitant of natural selection, an expanded theory of organismic evolution, including saltations, emerges.

Climatic Variations in the Eastern Mediterranean Sea Area

Abstract: A very dry climate which prevailed during the last glacial maximum of the Pleistocene from India to the Sahara, was replaced by variable weather conditions with alternating more or less humid phases, starting from the Pleistocene-Holocene transition period and lasting up to about 3000 years ago, when present arid conditions set in. A particularly wet phase is recognized throughout the region some 5000 years ago. Phase shifts within the region and in particular changes in rain distribution patterns, are interpreted as due to shifting spheres of influence of the monsoonal circulation, of Atlantic depressions and moisture originating from the Mediterranean Sea. The condition of the Mediterranean Sea itself, which is influenced by runoff and melt waters from the European Continent and by the Nile floods, as well as by the eustatic sea-level changes, is not a good indicator of local climate conditions.

Alkaloidal venom mace: Offensive use by a thief ant

Abstract: Eingegangen am 28. November 1979 1. Lecoq de Boisbaudran, F. : C.R. Acad. Sci. Paris C 100, 701 (1888); Nilson, L.F., Pettersson, O.: Z. phys. Chem. 2, 701 (1888) 2. Clark, R.J., Griswold, E., Kleinberg, J. : J. Am. Chem. Soc. 80, 4764 (1958) 3. Meyer, G.: Z. anorg, allg. Chem. 445, 140 (1978) 4. Poeppelmeier, K.P., et al. : Inorg. Chem. (ira Druck) 5. Morss, L.R. : J. Inorg. Nucl. Chem. 36, 3876 (1974) 6. Meyer, G., Dietzel, E. : Rev. Chim. Min6r. 16, 189 (1979) 7. Aizu, K. : J. Phys. Soc. Japan 27, 387 (1969)

Analysis of the acoustic orientation behavior in crickets ( Gryllus campestris L.)

Abstract: poorer growth. We undertook the present study to find compounds which, in our variant of Kidder and Dewey's medium [4], would shorten the extended doubling times. Preliminary experiments showed that increased concentrations of the components of the medium failed to do so. We included other Tetrahymet~ species in this study for comparative purposes. Table 1 shows the doubling times of the two Tetrahymena species calculated from several determinations of population densities during growth ranging from the initial value of 103 cells/m1 to densities of around 105 cetls/mI (technical details in [5]). We tested the effects of asolectin (a product of repeated acetone washings of commercial soybean lecithin containing approximately equal proportions of lecithin, cephalin, and inositol phosphatide, and a small amount of phytosphingosine) and a commercial grade of cephalin (phosphatidyl ethanolamine, L-~-cephalin, Sigma P 4264), both in concentrations of 5 rag/100 ml. The phospholipid preparations reduced the mean generation times to 55 and 70% (columns 3 and 4) of the control values shown in column 2, respectively. They also caused an appreciable reduction in the standard deviations of the generation times. The addition of phosphoglyceric acid, phosphoryl choline, and/ or fatty acids (oleic and linoleic) had no effect, which is in line with Soldo and Merlin's finding that the phospholipid molecule must be administered in its entirety in order to promote growth of the ciliate Parauronema [6]. Asolectin also shortened the doubling times of T. vorax, strains VzS and Tur, growing in a synthetic medium by ~30 and ~40%, respectively, in agreement with Shaw and Williams's results for the latter [7] ; moreover, it stimulated growth of the ciliates Glaucoma [8] and Colpidium in synthetic and peptone media~ respectively (unpuNished results). These results suggest that the synthesis of certain phospholipids, which, though unknown at this time, might possibly contain unsaturated fatty acids, represented the growth-rate-limiting process in these species. In contrast, such a phospholipid requirement for rapid growth is absent in the case of T. thermophila ('Fable 1, line 2). To date, this cell is the only ciliate known to grow almost equally fast in complex as well as in fully synthetic, lipid-free media. Kidder and Dewey's synthetic medium has been used as a starting point for developing nutrient media for other ciliates. Phospholipids, sterols, and unsaturated fatty acids often stimulate ciliate growth ([6, 8, 9], Table 1). The growth of mammalian cells in culture is often stimulated as welt by phospholipids, sterols, and unsaturated fatty acids [10]. Asotectin may prove to be a useful phospholipid preparation in attempts to make fastidious cells grow better in pure culture. We thank Prof. G.G. Holz, Jr., Department of Microbiology, State University of New York, Upstate Medical Center, Syracuse, N.Y., for a gift of asolectim D.D. gratefully acknowledges the receipt of a grant from The Danish Ministry of Education.

Sedimentary record of environmental pollution in the Western Baltic Sea

Abstract: The chronological development of environmental pollution in the Western Baltic Sea for the past hundred years was investigated in dated sediment cores. An artificial radionuclide (137Cs), nutrients, heavy metals, chlorinated hydrocarbons (PCB, DDT, Lindane) and plasticizers (phthalate esters) show characteristic distribution patterns within the various cores. They can be related to the production and use of specific chemicals and goods, to emissions associated with the increased combustion of coal parallel to industrialization and —in the case of 137Cs — to emissions associated with atomic weapons tests in the high atmosphere. Characteristic trends in the general development of pollution may be superimposed by specific emissions from local sources.

Ribosomal function and its inhibition by antibiotics in prokaryotes

Abstract: Most of the known antibiotics act at the level of protein biosynthesis probably due to the extraordinary complexity of the translational machinery which can be interfered with at many points. At first a survey is given of our present knowledge covering the structure and function of the prokaryotic ribosome. The most important antibiotics acting at the translational level are integrated into this network of data. The binding sites and the inhibition mechanisms of the drugs, together with the ribosomal components altered in resistant mutants are described. Finally, the points of interference with the translational machinery are indicated in an extended scheme of ribosomal functions.

Colony specificity in the trail pheromone of an ant

Abstract: Chemical cues which permit individuals in an ant colony to identify nestmates and aliens are common [1], but these colony odors are not only perceived by direct contact between workers. For example, harvester ants (Pogonomyrmex) from different nests are able to distinguish the scent of their own colony in their nest material [2], and also detect colony-specific signals in homing trails laid from secretions of the Dufour's gland [3]. In addition, African weaver ants, Oecophylla longinoda, use colony-specific pherg, mones present in rectal fluid to advertise territories [4]. Only in the latter example has the source of the specificity been identified. Here I report on the colony specificity of the trail pheromone of the formicine ant Lasius neoniger, and its ecological significance. L. neoniger, the most abundant ant species in North America, commonly occurs in open habitats where it mounts incredibly dense populations [5]. As many as five colonies have been recorded in a sqaure meter, and nest entrances of neighboring colonies are often as close as 4 cm. Each nest is composed of several nest craters, and associated with each crater is a group of foragers that exhibit strong site fidelity. In addition to this structural and behavioral subdivision of the foraging area of a colony is a more subtle partitioning. Workers leaving a nest entrance travel along persistent trunk trails and depart at various distances to forage individually [6]. Field and laboratory studies have shown that these trail systems arise from recruitment trails composed of hindgut material which contains an ephemeral stimulatory component and a more durable substance which functions as an orientation cue. In a binary choice test, workers were capable of discriminating between artificial trails composed of hindgut extracts prepared from nestmates from those of workers from conspecific neighboring colonies. The trail pheromone was extracted by crushing five hindguts in 50 gl 100% ethanol and solutions were prepared from hindguts of workers from two different colonies. Next, a Y-shaped pattern was drawn in pencil on a sheet of chromatography paper. The stem of the Y pattern was 3 cm long and the two branches, each 25 cm long, diverged at a 90 ~ angle. 1.5 p.l of hindgut solution prepared from workers from the colony to be assayed was deposited on the 3-cm stem of the Y with a microsyringe. This trail continued on one branch of the Y at a volume of 5 pl extract/ 25 cm. The other branch was composed of an equal volume of foreign extract. Workers from the test colony were then slowly baited to the base of the stem of the Y at which point the bait was removed. Recruited workers then followed the 3-cm stem to the junction of the two trails. Counts were taken in a 10-min period only of those ants that tropotactically contacted both trails and then continued on one for at least one-half its length. The results of three series of experiments are presented in Table 1. Clearly, workers of L. neoniger are able to discriminate their own trail pheromone from that of conspecifics. As a control, artificial trails prepared from the same extracts were offered to a third colony. There was no difference between the number of ants following either trail, therefore, concentration differences or conditioning effects were not responsible for the prefer-

Isolated pollen cultures and pollen dimorphism

Abstract: a Based on 0~4 rating where 0=no formation and 4=abundant formation. b Alternaria kikuchiana 15 B. infected by M. pinodes. A. kikuchiana 15B did not produce intracellular hyphae on any of the plant species tested, but established infection on 5 species of plants to which M. pinodes was pathogenic, in the concomitant presence of F 5. Thus the results indicated that the host specificity of M. pinodes coincided with the specificity of the biological activity of F 5. These results suggest that F5 produced by M. pinodes might be a determinant of pathogenicity to its host plant, breaking down the general defense reaction. Since F 5 did not cause any visible injury to pea leaf, stem, and isolated protoplasts prepared from pea leaf, it can hardly be a \"host-specific toxin\". Treatment of F5 with pronase reduced markedly its activity to suppress pisatin accumulation in pea leaf by subsequent inoculation with a nonpathogen of pea, S. sarcinaeforme. Amino acid analysis of acid hydrolysate of F5 purified by high-pressure liquid chromatography yielded three amino acids : aspartic acid, serine, and glycine at the ratio of 1:2:1. Thus an oligopeptide seems to be an essential part of the F 5 molecule.

Accuracy of sound localization in a miniature dendrobatid frog

Abstract: 1. Wilson, E.O.: The Insect Societies. Cambridge, Mass. : Belknap Press 1971 2. Hangartner, W., Reichson, J.M., Wilson, E.O.: Anita. Behav. 18, 331 (1970) 3. Regnier, F.E., Nieh, M., H611dobler, B.: J. Insect Physiol. 19, 981 (1973) 4. H611dobler, B., Wilson, E.O.: Proc. Nat. Acad. Sci. USA 74, 2072 (1977) 5. Wilson, E.O. : Bull. Mus. Comp. Zool. (Harvard) 113, 1 (1955) 6. Similar trail systems have been described in Formica [see Rosengren, R.: Acta Zool. Fenn. 133, 3 (1971)] and in Pogonomyrmex [see H611dobler, B. : Behav. Ecol. Sociobiol. 1, 3 (1976)] 7. See the review by H611dobler, B., in: Advances in the Study of Animal Behavior, Vol. 8, p. 75 (1978) 8. Huwyier, S., Grob, K., Viscontini, M.: J. Insect Physiol. 21, 299 (1975)

Die Ontogenese der retinotopen Projektion

Abstract: Recent evidence indicates that the retinotectal projection has a field-to-field rather than a point-to-point precision. Therefore, individual fibres can vary their relative position in the fibre pathway to some extent. In addition it is not necessary that retinotopy is maintained throughout the whole pathway; transformations may also occur. In fact, in the chick embryo outgrowing retinal fibres maintain not an absolute but only a high degree of order. Transformations occur at the entrance to the optic nerve and probably also right behind the chiasm. The origin of the map is determined by the fact that central retinal fibres which are formed first connect to tectal neurons near the centre of the optic tectum where neurons mature first. There they immediately invade the cellular tectal layers and form functional synapses soon after. Supernumerary fibres degenerate.

Species-specific proteins in fossils.

Abstract: With a solid-phase radioimmunoassay it has been possible to detect species-specific collagen and albumin fossils as old as 1.9 million years. This technique may provide new data on the genetic relations of fossil species to each other and to living forms.

Physics and mechanics of ice

Abstract: The increased technological activity in the Arctic and Antarctic areas has brought into focus the field of ice mechanics as presented at the symposium The main subjects were creep and failure of ice, but also engineering problems of ice forces, bearing capacity, icebreakers, icebergs and model ice testing have been covered