Showing papers in "Naturwissenschaften in 1984"

Foraging, echolocation and audition in bats

Abstract: Sympatrically living echolocating bat species search for prey in different foraging zones. Structure of echolocation calls and audition are adapted to the specific foraging areas and hunting behaviors. Long pure-tone and narrow-band echolocation signals are described as adaptations to long-range echolocation and to fluttering-insect detection in echo cluttering environments. Echolocation with brief broadband signals is discussed in context with target texture discrimination and range finding by measuring echo travel times. I n the history of mammalian evolution the bats (Chiroptera) provide an impressive story of success. The well preserved fossiles from Grube Messel near Darmstadt and from Wyoming, USA tell us that already in the wake of mammalian development, some 50-60 million years ago, bats had achieved a status of sophisticated design as perfect as in recent species. Chiroptera ramified into more than 900 different species indicating that they enjoyed a niche of living little impaired by competitors from other mammalian stock or vertebrate phyla. Bats owe this flourishing existence to two unique specializations: they extended foraging on insects from the ground and vegetation into the air by developing wings and escaped the strong predatory impact of the faster flying birds by restricting their foraging flights to the night. This they could achieve because they integrated vocalization and audition into an effective echolocation system [1]. Echolocating bats emit brief sounds of high frequencies (15-200 kHz) through the mouth or the nostrils and listen to the echoes reflected from prey and objects around them. Due to the limited energy available in emitted sounds and sound absorption in air echolocation only operates over shorter distances of maximally 30-40 meters. The information from the echoes provides the bat with an auditory representation of its surroundings precise and good enough to do without any visual information. Thus unlike owls echolocating bats skillfully fly and catch prey in complete darkness [2]. Echolocation has most probably evolved in context with catching flying insects which is illustrated by the fact that all but one genus of the frugivorous Megachiroptera do not echolocate at all, but instead feature excellent night vision. Even though some echolocating bats have specialized on eccentric food like pollen, fish, frogs or warm blood most species feed on insects. In this report I shall focus the discussion on the insect-eating species. Sound recordings from about 150 of the more than 600 echolocating bat species have disclosed that the structure of echolocation pulses are widely diverse (e.g. [3-6], and many others). The frequency of the main energy emitted may range from 17 kHz to over 200 kHz and sound duration may vary from 0.3 to 200 ms. Echolocation pulses might be brief frequency-downward-modulated sweeps (FM) consisting of one to several harmonics which broaden the frequency band of the signal to up to 120 kHz. In other species, notably horseshoe bats and hipposiderids, sounds consist of combinations of long pure tones, so-called constant-fre-

Das toxische Kompartiment der Pflanzenzelle

Abstract: Donnees sur la localisation infracellulaire des glycosides a potentialite toxique et des enzymes correspondantes. Examen des mecanismes responsables du transport de ces composes toxiques dans les vacuoles et de leur retention dans le suc vacuolaire

Superheavy organic carbon from hypersaline microbial mats

Abstract: Microbial mats from coastal brine pools of the Sinai Peninsula are consistently enriched in the heavy carbon isotope (13C) as compared to average organic matter, those from the Solar Lake locality representing the heaviest organic carbon ever encountered in the biosphere (~13C = 5.7 _ 1.4%0 vs. PDB). Ineffective discrimination against 13C in the carbon-fixing pathways of the mat-forming microbenthos seems due to substantially reduced CO2 solubilities in heliothermal brines pushing carbon into the exceptional role of a limiting nutrient, and the consequent establishment of a diffusion-limited assimilatory pathway in which the large isotope fractionations of the ribulose-l,5-bisphosphate carboxylase reaction are basically suppressed. C o m m o n photosynthetic pathways discriminate against heavy carbon (13C) ' principally as a result of a kinetic isotope effect inherent in the first carbon-fixing carboxylation reaction [1-3]. Consequently, biogenic substances display a marked bias in favor of 12C, the degree of enrichment in light carbon varying with the type of plant or autotrophic microorganism (Fig. 1 A). On average, the ~13C values* of organic carbon are some 20 to 30%o more negative than those of marine bicarbonate and carbonate, the most abundant inorganic carbon species in the environment. This holds for both the extant biosphere and the huge reservoir of sedimentary organic matter (\"kerogen\") that preserves the isotopic composition of the primary biogenic precursor materials with but minor change ([4-6, 12] ; see also Fig. 1 B).

Chemical identity of the chromophores of fly visual pigment

Abstract: vanced that nickel inhibits either the synthesis of SMM or the transaminase of homocysteine or its precursors. Synthesis of cysteine [7] and hence homocysteine occurs in leaves. If vase solutions containing nickel ions inhibit the leaf synthesis of cysteine and homocysteine that explains why our leafy Chrysanthemum blooms responded to nickel by delayed flower senescence, whereas the leafless blooms of Papaver nudicaule did not. Our thanks are expressed to Dr. V.J. Bofinger of the Department of Mathematics for statistical advice. Received December 8, 1983

Biomolecules are unstable under "black smoker" conditions

Abstract: The effects of high hydrostatic pressure on hydrolysis and hydrothermal degrdn. of amino acids, polyglycine, and thermophilic bacteria were studied. Most amino acids, after 6 h incubation on 250 Deg and 260 bar, pH 2 and 7.6, were transformed or decompd. Glycine, alanine, and NH3 increased drastically, suggesting that they are degrdn. products. To det. the stability of the peptide bond, polyglycine was subjected for 6 h to 253 Deg, 260 bar pressure at pH 7.0. Complete hydrolysis was found at 6 h. Similarly, Pyrodictium occultum cells incubated at 260 Deg, 260 bar for 6 h suffered pronounced hydrolysis and amino acid degrdn. The ability of thermophiles to survive at these high temps. is discussed.

Insemination controls the reproductive division of labour in a ponerine ant

Abstract: The control of oviposition in insect colonies is fundamental to the structure of their social systems. In most ant societies a distinct female caste performs the reproductive function, while the worker caste is sterile, or at the most produces trophic or unfertilized (male) eggs. Winged males and virgin queens are seasonally produced, and leave their nests on nuptial flights [1]. Thus a trend towards reproductive specialization and monogyny has accompanied the evolution of the division of labour. In contrast to this, we have found that colonies of the ponerine Ophthalmopone berthoudi reproduce by means of a large number of unspecialized egglayers. Wheeler and Chapman [2] recognized two distinct evolutionary patterns in the ponerines, one leading to the development of wingless ergatoid (=worker-like) queens as in Leptogenys, and the other associated with the complete disappearance of the queen caste and its replacement with fertile workers [3]. It is the latter unusual reproductive pattern to which we wish to direct attention. Wheeler and Chapman [2] observed a normal male copulating with a worker in Diacamma, a genus in which there are no queens. The fertile workers may be called gamergates ("married workers") to distinguish them from ergatoids. Work on a number of species with gamergates [4, 5] has documented that in each colony there may be one or more fertile workers which supply the eggs that develop into workers and males. Many features of such a reproductive system are still unknown, e.g. how are gamergates differentiated, can all workers mate and if so, what is the proportion of gamergates in a colony? Ophthalmopone berthoudi is an African species in which winged queens have never been found; it occurs in semi-arid regions and feeds on termites. Field observations in Mkuzi Game Reserve, South Africa, have shown that colonies consist of a number of distinct nests separated by various distances. Colony integration is maintained through the frequent transfer of adults and brood between the nests along non-chemical trails. Workers are produced for most of the year (with a hiatus in egg production before winter) and this results in a nest population with individuals of various ages. Single nests and nest complexes of O. berthoudi were excavated at different times of the year, and a large sample of ants from each unit was dissected. This included a sample of 100 above-ground ants which were all found to be non-reproductive. Dissection of 350 cocoons containing pharate adults never yielded any winged females. In each nest there are various numbers of egg-laying workers, all of which are indistinguishable from sterile workers by simple visual inspection. These fertile workers were found to have 3 enlarged ovarioles per ovary, with short strings of developing oocytes and very seldom more than two large fully formed eggs per individual. The ovarian apparatus of sterile workers was the same as that of reproductive ones, but the 6 ovarioles were undeveloped. Thus there are no distinct female castes. Examination of spermathecae revealed that ants with active ovaries had been inseminated, while ants with undeveloped ovaries had not been inseminated (Table 1). These data demonstrate that insemination triggers ovarian activity. This is not simply a correlation between the occurrence of the two events, since the male data reported below indicate that the relationship is a causal one. Were ovarian activity to be responsible for changes in worker behaviour which lead to mating, we would expect to find unmated workers with developed ovaries. None have been found at any time of the year. Indeed we can state that the haploid eggs which develop into males are laid by inseminated gamergates. Insemination also produced a change in the chemical composition of the mandibular gland pheromone of these ants and in their behaviour. The mated ants remained inside their nests for the rest of their lives, except when they were carried from one nest to another. They are removed from the normal sequence ' of age polyethism exhibited by their non-reproductive sisters. Males were only active above ground for a few weeks of the year (February to the beginning of March). Every day during this period a few males left their nests and flew off. They were seen to enter other nests and copulation occurred underground. Any ant that had not become active above ground prior to the period of male activity had a high probability of becoming inseminated and hence reproductive; this accounts for the large number of garnergates found in the nests sampled at this period (Table 1). Thus the sharp increase in the gamergate to worker ratio seen from February to March can be correlated with the pattern of male activity. During the rest of the year the proportion of gamergates usually decreased through the emergence of new non-mated ants. However, the wide variations over a one-year period seen

Regional differences in nitrogen and carbon isotopes on the continental shelf of the Gulf of Mexico

Abstract: The Gulf of Mexico has been characterized as a marginal ocean basin, bordered on the west by a landmass with numerous riverine inputs, and on the east by the Yucatan and Florida Straits which join it to the Atlantic Ocean [1]. Stable carbon isotope compositions of the organic matter from surficial sediments of the continental margin of the northwestern Gulf have been useful in distinguishing terrigenous organic material from that of marine origin [2]; however, small differences exist between the eastern and western shelf sediment 13C compositions [3]. Contrasts in benthic foraminifera assemblages have also been noted [4]. Stable nitrogen isotope analyses of particulate organic matter (POM), zooplankton, shrimp and sediments from these two regions amplify these distinctions and support a hypothesis of a difference in the primary sources of organic matter, which are based upon dissimilar inorganic nitrogen sources. Stable carbon isotope ratios have been used routinely to trace the formation and cycling of organic matter in the marine environment. As a consequence of both nitrogen and carbon isotope ratios having distinct values for given reservoirs, ~SN analysis can provide valuable independent information in the resolution of sources of organic matter when ~3C data are insufficient [5, 6]. Furthermore, specific chemical reactions affect only the nitrogen of an organic substance so that isotopic fractionations and distributions of 15N are

Specification of tecto-motor outflow in toads by antidromic stimulation of tecto-bulbar/spinal pathways.

Abstract: Die hier vorgestellten Sensillen gleichen Luftstr6mungssinnesorganen auf dem Kopf yon Loeusta migratoria L. (Orthoptera, Acrididae), wie sic in [2] beschrieben wurden. Fig. 2. Lichtmikroskopische Aufnahme eines L/ingsschnitts durch ein Sensillum des fiinften Pereiopoden von G. roeselii (9) aus der Ahr (x300). Zu erkennen sind Haarschaft (Hs), Haarbecher (Hb), Dendrit (D) und zwei Hfillzellen (Hz)

The structure of the blue starch-iodine complex

Abstract: Systemes modeles pour l'etude de la structure de chaines polyiodures. Etude par diffraction RX et spectrometrie Raman en solution

Magnetic field of the earth as additional zeitgeber for endogenous rhythms

Abstract: The influence of 50% decrease and increase of the earth magnetic field on the activity of the enzymes hydroxyindole-O-methyltransferase (HIOMT) and N-acetyl-serotonintransferase (NAT) is proved in vivo and in vitro. NAT and HIOMT catalyse the melatonin biosynthesis in the pineal gland and in the retina. Our results support the hypothesis of Leask and Schulten, that molecular magnetic field sensitivity is the basis of animals' magnetic field detection.

“Myzocytosis”, a kind of endocytosis with implications to compartmentation in endosymbiosis

Abstract: 1. Smith, B.N., Robbins, M.J. : Proceedings of the Third International Congress on Photosynthesis, p. 1579. Amsterdam: Elsevier 1974 2. Nobs, M.S., et al.: Carnegie Inst. Wash. Yearb. 69, 625 (1971) 3. Belford, H.S., Thompson, W.F. : ibid. 76, 246 (1977) 4. Bouton, J.H., et al.: Plant Physiol. 67, 433 (1981) 5. Ku, S.B., et al. : ibid. 71,944 (1983) 6. Powell, A.M.: Ann. Missouri Bot. Garden 64, 590 (1978) 7. Apel, P., Maas, I.: Biochem. Physiol. Pflanzen 176, 396 (1981)

Evidence for an extracellular lytic compartment of plant cell suspension cultures: the cell culture medium

Abstract: On met en evidence qu'une partie importante des enzymes vacuolaires est secretee dans le milieu de culture des cellules en suspension

[X-ray microscopy].

Abstract: Owing to the short wavelengths of X-radiation X-ray microscopes allow higher resolution than optical microscopes. In contrast to electron microscopes, X-radiation can be used to study relatively thick aqueous specimens in their natural environment. X-ray microscopes require intense X-radiation, which is best provided by electron storage rings, as well as efficient X-ray optics. X-ray microscopes with zone plate optics are installed at the storage ring BESSY in Berlin for studies in the fields of biology, medicine, biophysics, colloid chemistry, and soil sciences.

Seasonality in freerunning circadian rhythms in man

Abstract: Retrospective analysis of data collected over 15 years in normal subjects isolated from time cures showed seasonal rhythms in the circadian period of the core temperature rhythm, in the amount of sleep (both shorter in spring and longer in autumn), and in the incidence of internal desynchronisation (most often in summer). Women slept longer than men at all times of year.

Vacuum energy in a Friedmann-Lemaître cosmos

Abstract: The age of our Galaxy has been derived from two different sets of Th/U ratio measurements in meteorites to be 20.8 (+ 2, 4 ) or (17.6 +4)109 years [28, 27]. This implies a lower limit for the age of the universe of 14.10 9 years if we accept the method as reliable cosmic chronometer. A consequence of this is that solutions of the Einstein-Friedmann equations with zero cosmological constant A are only possible if the present Hubble parameter H 0 < 7 0 k m s l M p c 1 (see Fig. 4 of Par t I of our review [2]). On the other hand derivations of the Hubble parameter from observations span a range from 50 (+ 10, 7 ) E24] to 100 ( 1 0 ) kms -1 Mpc -1 [4]. At the Patras meeting of the International Astronomical Union the value of 75 was favoured. The acceptance of this value would imply that solutions of the Friedmann equations require values of the cosmological constant A which correspond to an equivalent constant vacuum density P~>Po, where Po is the present matter density of the universe. This situation has prompted us to reinvestigate solutions of the cosmological equations with nonzero A, An average value of the present density of the baryonic matter po,B = 0 . 5 . 1 0 3 ~ -3 has been derived from the primordial 4He and 2H abundances. This value is independent of the special choice of the Hubble parameter. Quantum field theory permits to interpret A as vacuum energy density C 4 ,%=pvc 2 -A (1) 8riG

Isolation and cultivation of mature oligodendroglial cells.

Abstract: CNS axons are ensheathed by myelin which is produced and maintained by oligodendrocytes. A disorder of this assembly results in functional disturbances, e.g., paralysis in multiple sclerosis. Methods are now available to isolate and cultivate oligodendrocytes in vitro. Thus, basic oligodendroglial properties can be now investigated: signals for oligodendroglial gene expression and their role in myelinogenesis and the interaction between oligodendrocytes and other neural cells by, e.g., the release of informational substances.

A new ornithischian dinosaur from the Triassic of North America

Abstract: Ornithischians, which rank among the best known and most diverse groups of dinosaurs, ranged throughout most of the Mesozoic, but their early history is obscure. Knowledge of the oldest ornithischian, Pisanosaurus , from the late Triassic Ischigualasto formation of Argentina is based on fragmentary and tantalizing evidence [1]. Several doubtful ornithopods from the late Triassic deposits of Nor th Carolina, Nova Scotia, Pennsylvania, Arizona and Texas are listed as indeterminate fabrosaurids [2], but the material being poorly represented, never received any formal name or diagnosis. During the TriassicJurassic transition, the ornithischians became geographically widespread, as their fossils have been found in South Africa [3 5], China [6], and Arizona [7]. The age of these ornithischianbearing horizons is controversial, ranging from Upper Triassic to lower Jurassic [8]. The new fossil f rom Texas described here is the earliest adequate record of an ornithischian found to date in Laurasia, and gives an insight about the origin and evolution of this interesting group of dinosaurs. The material is represented by partial jaws with well-preserved teeth, a dorsal vertebra, and an astragalus. The presence of lateral mandibular fenestra and the thecodont type of tooth implantation suggests its archosaurian affinity. The astragalus is of standard dinosaurian pattern with an ascending process for locking the tibia. The compressed, leaf-like form of its teeth, with denticulated edges, is like that of ornithischians. The teeth are marginally placed, not inset, and continue to the tip of the premaxilla. The teeth are not worn down by toothtotooth contact. The tooth crown is symmetrical with practically no curvature of the dentary tooth laterally. These dental characters are diagnostic of the family Fabrosau,, / / \" / , / \\ \\ J ~\\ ' ' / b

Magnetic field induced temperature change in mice

Abstract: seem small, however, given the high baseline stability and the near impossibility to elicit any frequency change to all kinds of stimuli or disturbances in this fish [4], except temperature change and specific, jamming electric stimuli, the change is considerable [2]. In addition, jamming stimuli elicited only frequency increase (up to a few Hz), not decrease. The present results demonstrate a tranquillizing effect of chlorpromazine also for the EOD of high-frequency, highprecision electric fish. Interestingly, formaldehyde-induced fluorescence histochemistry (Falck-Hillarp technique) combined with microspectrofluorometry showed that, among many other structures, the neurons of the medullary pacemaker nucleus which commands the electric organ contain biogenic amines (catecholamines) in the brain of Eigenmannia, a related gymnotiform fish [5]. The animal model presented here appears suitable for the investigation of the behavioural effects of psychoactive drugs. It offers speed, accuracy and simplicity over the more complex ethological methods, as employed in [3].

Learned enemy specification in the defense recruitment system of an ant

Abstract: Les resultats de l'etude effectuee sur Pheidole dentata montrent que l'apprentissage contribue aux reactions de defense contre un ennemi specifique

Carcinogenic N-nitroso compounds and their environmental significance

Abstract: A short review is given on the potent and organ-specific carcinogenic effects of N-nitroso compounds. Like many other chemical carcinogens, nitrosamino compounds require activation in vivo via enzymatic alpha-hydroxylation to form alkylating agents as ultimate carcinogens. Since no epidemiological data in man are available, extrapolation of animal data to man are important as well as dose-response studies in risk evaluations. Important aspects of these problems are presented. Finally the environmental impact of N-nitroso compounds is summarized.

On the use of plants and plant-derived compounds for the control of schistosomiasis.

Abstract: The rising costs of chemotherapy and synthetic molluscides have led to an increasing interest in plants which are lethal to the intermediate host of schistosomiasis (bilharzia). Over one thousand species have been tested but only a few have been phytochemically examined. Approximately fifty molluscicidal compounds have so far been isolated from plants, including saponins, terpenoids, flavonoids, naphthoquinones and tannins. The saponins from Phytolacca dodecandra are the most active and have been successfully employed in field tests. The latest results in this area and the problems involved in the use of plants and natural products for the control of schistosomiasis are discussed here.

Neurophysiological data regarding motor pattern generation in the medulla oblongata of toads.

Abstract: cial Insects, Vol. IV, p. 157 (H.R. Hermann, ed.). New York: Academic Press 1982. Note that the Dorylinae are probably triphyletic (see Gotwald, ibid.) 2. Franks, N.R., Fletcher, C.R.: Behav. Ecol. Sociobiol. 12, 261 (1983) 3. H611dobler, B., Lumsden, C.J.: Science 210, 732 (1982); H611dobler, B.: Behav. Ecol. Sociobiol. 1, 3 (1976) 4. For example, Neivarnyrmex nigrescens (Schneirla, T.C.: Anim. Behav. 11, 583 (1963)) 5. My use of the term ' solitary foraging' (to contrast with 'group foraging') encompasses foraging types I-IV of G. Oster 6. 7.

Complexation gas chromatography

Abstract: High-resolution complexation gas chromatography with chiral metal chelates offers a valuable tool for the stereochemical analysis of volatile oxygen-containing insect pheromones. The major advantages of the method are: high selectivity of the stationary phase; high sensitivity (nanogram range); high accuracy (Δee ≦ ± 1% for 0 < ee < 100); the selectivity of the stationary phase can be adjusted to the analytical problem by an appropriate choice of the metal chelate; derivatization steps prior to the analysis may be omitted. The exact knowledge of the stereochemistry of chiral pheromone constituents may improve the understanding of the chemical communication system of insects and may clarify the biosynthesis of pheromones as well as evolutionary implications thereof. A deeper insight into the communication codes will help to optimize synthetic pheromones or pheromone mimics which may be used to control insect populations with a minimal amount of pesticides.

A volatile leafcutter ant repellent fromAstronium graveolens

Abstract: 1. Krieter, M., in: Hatzfeld, H.: Stirbt der Wald? 1982 2. Matthias, U., Meinel, W. : Phillipia 5 (1), 76 (1982); Krebs, A.: Dissertation Uni. Tfibingen 1979; Hecker, A.: Diplomarbeit Uni. Mfinchen 1982 3. Schoen, R., Wright, R.F., Krieter, M.: Acid Rain Res. Rep. 5/84, NIVA, Oslo (in Vorbereitung) 4. Henriksen, A.: Vatten 38, 83 (1982); Wright, R.F., Henriksen, A.: Limnol. Oceanogr. 23, 487 (1978) 5. Wright, R.F: Acid Rain Res. Rep. 4/83, NIVA, Oslo 6. OECD: Long-Range Transport of Air Pollutants, Paris 1976 7. Wright, R.F., etal., zit. in: Overrein, L.N., Seip, H.N., Tollan, A. : Final Rep. SNSF-Projekt, Oslo 1980; Grahn, O.: Water, Air, Soil Poll. 7, 295 (1977); Dillon, P.J., et al., in: Ecol. Impact Acid Precip., Int. Conf. Sandefjord, Norway 1980 8. Baker, J., Schofield, C.L.: Water, Air, Soil Poll. 18, 289 (1982) 9. Ulrich, B., in: Landwirtschaft und Wasserhaushalt, S. 212 (F. Fischbach, Hrsg.). Verlagsunion Agrar 1981