Showing papers in "Naturwissenschaften in 1979"

Biosynthesis of cyanogenic glycosides

Abstract: Cyanogenic glycosides are secondary plant compounds that occur widely in the plant kingdom. They are the source of HCN which can render the plant toxic if it is taken as food. The enzymes responsible for production of the HCN have long been known. More recent biosynthetic studies have established certain protein amino acids as precursors of the aglycones, and indicate N-hydroxyamino acids, aldoximes, nitriles and α-hydroxynitriles as intermediates. In sorghum the several biosynthetic enzymes catalyzing the flow of carbon atoms from l-tyrosine through such nitrogenous intermediates are located in a membrane fraction and may be capable of metabolic channeling.

Reception of particle oscillation in a medium — an unorthodox sensory capacity

Abstract: The oscillation of particles in a medium is the adequate stimulus for specialized receptors. Such receptors can be found in nearly all phyla in the animal kingdom. Specialized sensory hairs in arthropods are used here as an example to show conditions and limits of vibration reception in a medium. The use of this sensory capacity in biologically relevant situations is shown on some well-known examples.

Pheromones are involved in the control of sexual behaviour in birds

Abstract: high degree. The high degree of acidification and the carbon assimilation of this crop plant as evidenced from the present investigation provide the physiological basis for its known survival under a semiarid tropical environment. The fact that the CAM behavior has been observed for the first time in this field crop should lead to further survey of other tropical crops. This investigation was partly supported by the Indian Council of Agricultural Research, New Delhi. Thanks are due to Prof. Dr. M. Kluge, Darmstadt, for his helpful comments. Received September 28, 1978

Zellwandstrukturen bei Methan-Bakterien

Abstract: None of the representatives of the four genera of methanogenic bacteria available in pure culture were found to contain the typical cell-wall polymer (murein, peptidoglycan) found in all other bacteria and cyanobacteria. However, each of the four genera contains different cell-wall polymers, indicating a very early divergence not only of the methanogens from all other procaryotes, but also of the various genera of the methanogens from one another. This assumption is compatible with the dendrogram of bacterial evolution derived from comparative cataloguing of the 16 S rRNS of bacteria.

``Arabidobrassica'': Plant-genome engineering by protoplast fusion

Abstract: After fusion of somatic cells (isolated protoplasts) of Arabidopsis thaliana and Brassica campestris, plants could be regenerated in which genetic material from parents of taxonomically different tribes is combined. Between these regenerants asymmetric hybrids have also been obtained, in which one parental genome is represented by reduced chromosome numbers. Results concerning the analysis and genesis of these plants are used to discuss the question whether such monster plants are of any importance.

Fossil evidence for a novel series of archaebacterial lipids

Abstract: coprostanol supply. Konstanz is the largest harbor city in the lake area and thousands of people either arrive at or depart from Konstanz each day during the summer. The direct disposal of feces by passenger ships was banned in 1976, but legislative measures were slow to develop; the input of human excreta from pleasure boats will only be prohibited by law in the course of 1979. A comparison of the coprostanol concentration from the uppermost sediment layer of our core with data from literature on surface sediments from marine environments (Table 2) shows that concentrations in the Konstanzer Trichter are comparable to those found in sediments in close proximity to sewage outfalls or sewage dumping zones in the New York Bight and the Clyde Estuary. The coprostanol concentrations of the sewage sludge introduced into these areas are also given for comparison. The Konstanzer Trichter levels are nonetheless still well below the extreme concentrations in the Tokyo Bay, which is known to be one of the most heavily polluted environments in the world.

Olfaction and homing in pigeons. A problem of navigation or of motivation

Abstract: get a statistical significant difference between the laboratory reared R. ridibunda and R. ridibunda from the field (p < 0.005) and highly significant difference between the wild caught R. escutenta and all other groups (p < 0.001). ]'he results of tile present irlvestigation provide strong evidence that R. ridibunda, a species that always hibernates beneath the water surface, fails to occur in waters with severe winter oxygen deficiency. They Received January 18, 1979 \\ \\

Preferred intervals in the spontaneous activity of primary auditory neurons.

Abstract: 1. Buschinger, A., Winter, U. : Insectes Sociaux 24, 183 (1977) 2. Faber, W. : Pflanzenschutz-Ber. 39, 39 (1969) 3. G6gwald, K. : Z. wiss. Zool. 136, 464 (1930) 4. GfBwald, K.: ibid. 144, 262 (1933) 5. Wesson, L.G., Jr.: Trans. Amer. Ent. Soc. 68, 98 (1939) 6. Wesson, L.G., Jr. : Bull. Brooklyn Ent. Soc. 35, 37 (1940) 7. Wilson, E.O. : The Insect Societies. Belknap Press of Harvard University Press 1971

Function of cyanelles in the thecamoeba Paulinella chromatophora

Abstract: the large curvature of the crystal planes, presenting a picture very different from the classical one of a crystal with atoms on parallel rows. The radius of curvature of the bent part of the crystal shown in Fig. 1 c is approximately 1200 A. Also to be noted is the remarkable tenacity of the spinel slabs even when severely elongated. In the light of these results, it is clear that mechanical degradation of the eIctrolyte is intimately associated with sodium loss from the interior of crystallites. Thus to make long-life batteries either the fi'-alu-mina must be stabilized against sodium loss or the electrolyte must be solely fl-alu-mina. EndosYmbioses between blue-green alga-like organisms and representatives of the Protozoa (cyanomes) are extremely rare. One of these fascinating associations is the thecamoeba Paulinella chromatophora Lauterborn which is regularly found living in symbiosis with two sausage-shaped inclusion bodies resembling blue-green algal cells. These bodies are generally termed cyanelles and are thought to function as chromatophores, thus permitting the thec-amoeba to live autotrophically [1]. During cell division of the thecamoeba the cyanelles are distributed to the daughter cells where they divide. Ultrastructural observations have demonstrated that each cyanel!e is enclosed within a vesicle of the host cytoplasm and that it shows the most essential characters of a blue-green alga [2]. No physiological characterization of this symbiotic association has hitherto been reported, possibly due to difficulties in obtaining sufficient quantities of the thec-amoeba. All attempts to cultivate Paulinetla or its isolated cyanelles have so far been unsuccessful. However, the recent development of some analytical procedures on a microscale [3] enabled us to start an experimental series with only 50 individuals of Paulinella per experiment. Incubation of P. chromatophora in a H14COg medium in the light showed that radiocarbon is photosynthetically assimilated. This light-dependent carbon incorporation is attributed to the presence of cyanelles within the host. The assimilation rate as based on the total carbon content of the incubation medium used is in the range of 5 pmol CO2/h per cyanelle. This value is of the same order of magnitude as with blue-green algae in the free-living state, if equivalent rates of photosynthesis expressed in a usual reference system are referred to cell numbers, as has been shown in similar experiments using Nostoc commune and Gloeotrichia echinulata. Itence the cyanelles of P. chromatophora may be regarded as normally photosymhe-sizing endosymbiotes. When extracts of Paulinella which had previously …

O 2 and H 2 S coexistence in stromatolites

Abstract: The coexistence of O2 and H2S in recent microbial mats is demonstrated. Oxygen and H2S are not only coexisting in considerable concentrations within recent stromatolites but high concentrations of the respective gases occur in alternating laminae. This “sandwich structure” is produced by alternating populations of oxygenic and anoxygenic photosynthetic bacteria and cyanobaeteria. The finding of such conditions may explain the alternation of oxidized and reduced iron minerals in Precambrian stromatolites and possibly also in the banded iron formations (BIFs).

Heterosis in the common European water frog

Abstract: when arranged in the shape of a cross. It can be assumed that the animals, which have congregated at the final destination, are oriented in an approximately vertical position with symmetrical stimulation on both sides or more exactly: in 2 perpendicularly oriented planes and that they strive to reach this destination. The animals are thus induced to migrate when it is impossible for them to achieve symmetrical stimulation in the vertical position. This is what happens in unilaterally symmetrical brightness patterns, for example, similar to those which can be found in lake regions near the shore. The spatial position dictated by the brightness pattern is thus the cause of "Uferflucht", i.e., avoidance of the shore. This capability of pelagial zooplankters to orient themselves in space is in marked contrast to related organisms which inhabit the litoral zone in lakes [5]. Since the pelagial rePresentatives execute daily periodic vertical migration without exception, one can assume that the afore-mentioned orientation in space is suitable to ensure the vertical orientation necessary for vertical migration with (or without) concomitant geotactic orientation. This orientation can therefore be evaluated as an adaptation to the pelagial habitat and ,,Uferflucht" can be evaluated as a by-product of this adaptation. It goes without saying that similar brightness patterns also exist in pelagial regions remote from shore as well as in regions close to shore, e.g., due to uneven cloud cover, the rising or setting sun, etc. Unlike the lake region close to shore, however, the position of the light and dark fields are subject to a change as a function of time so that obvious differences in the horizontal distribution cannot be expected.

Incorporation of inositol hexaphosphate into intact red blood cells. I. Fusion of effector-containing lipid vesicles with erythrocytes.

Abstract: Fluid charged lipid vesicles loaded with an inositol hexaphosphate solution were used to transport this allosteric effector into human intact red blood cells. Rate and extent of uptake of the vesicles and of the effector by the red blood cells were measured as changes in the O2 half-saturation pressure and the 31P-NMR spectra of the intracellular inositol hexaphosphate-haemoglobin complex.

Brain growth during the adult stage of a holometabolous insect

Abstract: Investigations of the gowth pattern in cerebral development of insects by volumetric determinations [1] and cell counts [2, 3] usually are discontinued at the stage of newly hatched imagines, because no significant changes are assumed to occur in further ontogenesis [4]. Here we present results which demonstrate that the growth of the brain in a holometabolous insect (Coleoptera) is not terminated after metamorphosis. Rove beetles of the genus Aleochara Grav. (Staphylinidae) and their larvae, which live as ectoparasitoids in pnparia of cyclorrhaphous Diptera, have been investigated in our laboratory with regard to their cornplex behavioral repertoire [5]. In this connexion the postembryonic development of the nervous system in A. curtula Goeze was examined histologically and by morphometric measurements. Changes of the brain were found in the early phase of the adults (Fig. 1), which are living up to 3 months in our cultures. In adults of A. curtula of the same size the absolute volume of the brain (the rind containing the cell bodies and neuropil) inci:eases by about 46% during the first 20 days after leaving the cocoon, independently of sex. A significant growth can be observed in the protocerebrum and deutocerebrum which amount to 58 and 38%,

Participation of toxin in wilting of Japanese pines caused by a nematode

Abstract: Wilting of Japanese pines (Pinus densifolia and P. thumbergiO, the most serious forest disease in Japan just as the Dutch elm disease in North America, was found recently to be caused by a nematode, Bursaphelenchus lignocolus Mamiya et Kiyohara [1], which is transmitted by a cerambycid beetle, Monochamus alternatus Hope [2]. This disease is spreading epidemically throughout central to south-western part of Japan. In spite of the well established life cycle of the pathogenic nematode [3] and the controlling method of this disease [4], the detailed mechanisms of the rapid wilting of pine trees remained obscure. The pathogenic nematode, B. lignocolus was cultured on the mycelia of Botrytis cinerea grown on the potato sucrose agar medium in Petri dishes at 25 ~ for 2-3 weeks. The pathogenicity of nematode or toxicity of the metabolite was determined by injecting the nematode or 25 gl of the metabolite solutions into the stems of 1month-old pine seedlings which were grown on wet cotton in Petri dishes at 25 ~ under artificial illumination. As shown in Table 1, all pine seedlings wilted within 4 days after inoculation with living nematodes (10 nematodes/seedling).

Towards an experimental analysis of molecular self-organization and precellular Darwinian evolution.

Abstract: An experimental system is described, which opens up a novel pathway towards a molecular understanding of the origin of life. The systemic conditions for the evolution of biological macromolecules are investigated in detail.

Antidot gegen urotoxische Wirkungen der Oxazaphosphorin-Derivate Cyclophosphamid, Ifosfamid und Trofosfamid

Abstract: under whole-body hyperthermia (40%) and hyperglycemia the triggering of the blood-flow stop needs only a local shortterm hyperthermic shock whose duration is dependent on the heat-exchange time in the tissue (about 30 min) [5]. In this situation, experimental evidence for the onset of a selective inhibition of microcircnlation is of topical interest. First indications could be obtained from the detection of an additional pH decrease during CMT hyperglycemia shortly after the onset of local hyperthermia at 42 ~ This phenomenon is based on lactic acid accumulation due to the arrested microcirculation [10]. Moreover, the decrease of microcirculation has been studied using a photoelectric fiber optic device for measuring the Evan's blue concentration in DS carcinosarcomas of rats during C M T hyperglycemia at different hyperthermic temperatures [11]. Thereby, a drop ofmicrocirculation down to 0.5% of the initial value was measured at pH 6.1 in the tumor and at 40.8 ~ hyperthermic temperature [11]. After this treatment, the tumors were immediately excised and fixed with formaldehyde. Histological examination (trichrome staining according to Goldner) resulted in the p ic tu re shown in Figure l a. The complete occlusion of the tumor microvasculature caused by the CMT process can be seen clearly. For comparison, Figure l b demonstrates a section of an untreated DS carcinosarcoma (control) of approximately the same size ( ~ 10 g). The selective and irreversible stop of. blood flow in the cancer tissue region must necessarily lead to tumor regression. In fact, we observed this phenomenon in animal experiments. In series with 20 DS carcinosarcoma-bearing rats, 40% of the animals were cured by applying only the two steps: tumor-tissue hyperacidification at pH ~ 6.1 and tumor hyperthermia at 42.5 ~ [12]. In another 20-rat series with pH 5.5 to 5.9 and <43 ~ hyperthermia of only three rain duration we obtained total regression of the 10to 15-g tumors within 21 days in 35% of the cases. Moreover, the occlusion of the vessels has the advantage that the toxic degeneration products of the decaying tumor can no longer pass into the circulation directly and rapidly (minor stress to the patient in the posttherapeutic phase). Further histological findings depending on variants of C M T treatment and on different time span between C M T treatment and Fig. 1. DS carcinosarcoma (rat), trichrome staining according to Goldner. (a) After selective triggering of stases in the terminal capillary network caused by a hyperthermy shock (41 ~ at pH 6.1 in the tumor tissue (CMT process). The blood vessels are dilated and filled with devitalized erythrocytes (occlusion). (b) Without CMT treatment. Only few viable erythrocytes in normally dilated capillaries can be detected

The inorganic biochemistry of nitrogen bioenergetic processes

Abstract: Redox conversions of inorganic nitrogen compounds are used by nitrate respiring, denitrifying and nitrifying bacteria to drive electron-transport phosphorylation. A preliminary understanding of these processes with respect to participating components and reaction sequences has now emerged. In particular, recent work suggests an involvement of membrane phenomena of chemiosmotic origin.

Methanogene Bakterien: Ungewhnliche Zellkomponenten und Stoffwechselwege in einer Bakteriengruppe mit phylogenetischer Sonderstellung

Abstract: Methanogenic bacteria area diverse group of anaerobic procaryotes that ferment CO2 plus H2 to CH4. Besides their unusual energy metabolism they are unique in that their cell walls do not contain murein, and in that their cell membranes are composed of isoprenoid lipids. Coenzymes occur which are not found in any other living organism. The translation apparatus differs, e.g., in not being affected by antibiotics known to be inhibitors of procaryotic protein synthesis. Most of the methanogens can grow on CO2 as sole carbon source; autotrophic CO2 fixation does not, however, proceed via reactions of the Calvin cycle. Molecular genealogical analysis has revealed that methanogenic bacteria constitute a grouping phylogenetically distinct from most other procaryotes.