Showing papers in "Naturwissenschaften in 1993"

A state of the art structural concept for humic substances

Abstract: In a recent communication [1] we presented a carbon skeleton for humic acid (HA) based on extensive mass spectrometric data in which alkylbenzene structures played a dominant role. We now show a more complete version of this structure in which we have inserted oxygen, hydrogen, and nitrogen atoms in conformity with analytical data obtained on many naturally occurring soil HAs. Oxygen is present in the form of carboxyls, phenolic and alcoholic hydroxyls, carboxylic esters and ethers, and nitrogen in heterocyclic structures and as nitriles. The elemental composition of the HA structure (Fig. 1) is C308H328090Ns, with a molecular weight of 5540 Da, and an elemental analysis of 66.8 % C, 6.0 % H, 26.0 % O, 1.3 % N. There are different views in the literature on soil organic matter as to whether carbohydrates and proteinaceous materials are adsorbed on or loosely retained by H A or whether they are bonded covalently to H A [2-5]. But regardless of which mechanism is considered, carbohydrates and proteinaceous materials are H A components for analytical purposes; their presence affects the elemental analysis and functional group content of HAs. Carbohydrates have been reported to account for about 10 % of the H A weight [6]; a similar value has been suggested for proteinaceous materials in H A [5]. Thus, let us assume that one molecular weight of HA interacts with 10 % carbohydrates and 10 % proteinaceous materials. The resulting H A has then an elemental composition of C342H38sO124N12 , with a molecular weight of 6651 Da, and an elemental analysis of 61.8 % C, 5.9 % H, 29.8 % O, and 2.5 % N. If more carbohydrates and proteinaceous materials are added, the C content of the HA decreases and the O content increases. The elemental composition and functional group content of HAs extracted from soils belonging to three different Geat Soil Groups as well as similar data for the proposed H A structure (after inclusion of carbohydrates and proteinaceous materials) are shown in Table 1. A comparison of the data indicates that the analytical features of the proposed H A structure are in general agreement with those of HAs extracted from soils. The HA structure shown in Fig. i is the result of extensive pyrolysis-GC/MS [7] and pyrolysis-FIMS [8], 13C NMR [9], chemical [10], oxidative and reductive degradation [ll, 12], colloid-chemical [13] and electron microscope [14] investigations done on HAs over many

The chemical nature of nitrogen in native soil organic matter

Abstract: H. Knicker, R. Frtind and H.-D. Ltidemann Institut for Biophysik und physikalische Biochemie der Universit~it, W-8400 Regensburg, FRG Fossil fuels and soil organic matter (SOM) together contain approximately five times more carbon than the biota and the atmosphere. Of this, soil organic matter accounts for about 30 % of the carbon present. In addition, SOM has an average carbon/nitrogen ratio of 10/1 and contains a huge fraction of the total ni- trogen available for plant growth [1]. Taking into account that the abundance of nitrogen in the earth's crust is much lower than that of carbon, this is a signif- icant fraction of the total nitrogen acces- sible to the biosphere. Under natural soil conditions, without the addition of miner- al fertilizers, SOM provides the majority of the nitrogen necessary for plant growth. It is also thought to be respon- sible for the interaction between agricul- tural biocides and the soil [5-7]. The chemical structure of this ubiquitous material, SOM, and especially the chem- ical nature of the nitrogen are thus of great and general importance. The mo- lecular structure of the nitrogen- containing fraction is, however, still a matter of controversy [2-4]. Structural models based on partial chem- ical analysis claim that a significant part of the nitrogen is present in the form of heteroaromatic structures, while NMR- spectroscopic studies on lSN-enriched composts and recent humic material found approximately 85 % of the signal intensity in the amide/peptide region of chemical shift and no signals in the range typical for heteroaromatic nitrogen. A major fraction of the native soil organic matter has been in the soil for several hundred to several thousand years [8, 9]. Compared to these time spans, laboratory-produced material has been fermented for at most 1 year, and it could be argued that heteroaromatic structures are only produced after much longer fermentation periods. This criti- cism may be overcome by the study of lsN-CPMAS spectra of soil organic mat- ter with natural lSN levels. This has not been achieved hitherto, because the low natural abundance (0.4 %) and the small gyromagnetic ratio of the 15N nucleus and therefore its low sensitivity in NMR experiments appeared to make this experiment an impossible one. The most abundant 14N-isotope (99.6 %) cannot be studied by high-resolution NMR because its large nuclear quadrupole moment leads to very broad and unresolved signals, especially in solid-state NMR [101. In previous systematic studies on 15N- enriched composts and organic soil extracts [11] our group optimized all spectral parameters for the ~sN-CPMAS experiment. A crude estimate showed that it should be possible to obtain 15N spectra with a tolerable signal-to-noise ratio after the accumulation of approximately one million transients. In the present paper we report on the first successful results of such experiments. Six German soils were studied as detailed in Table 1. In Figs. 1 and 2 some of the spectra obtained are shown. They fully corrobo- rate the conclusions drawn from the stud- ies of short-term composting exper-

Resistance to fungal diseases in transgenic tobacco plants expressing the phytoalexin elicitor-releasing factor, β-1,3-endoglucanase, from Soybean

Abstract: Plant resistance responses, as exemplified by the production of antifungal phytoalexins, appear to be invoked by specific molecules elaborated by fungal pathogens, termed elicitors [1]. Our previous studies with the soybean-fungal pathogen Phytophthora rnegasperma f. sp. glycinea system indicated that elicitors of phytoalexin production exist in fungal cell walls as insoluble, bound forms [2]. During infection, however, these elicitors were solubilized by a factor contained in soybean tissues such that they are recognized by a plant receptor [3]. The elicitor-releasing host factor was purified and shown to be [31,3-endoglucanase [4] and its cDNA was subsequently cloned and characterized [5]. Unlike certain other observations [6], the soybean endoglucanase did not directly inhibit several fungal pathogens, including those used here ([7], authors' unpublished data). Thus, soybean [3-1,3endoglucanase appears to be a key enzyme involved in the generation of elicitor signals leading to active disease resistance. Here we report that transgenic tobacco plants expressing the soybean glucanase gene exhibit high levels of resistance to fungal diseases. Plants transformed with Agrobacterium turnefaciens harboring sense or antisense orientations of two soybean [3-1,3endoglucanase cDNA contained D N A that hybridized with the soybean glucanase when analyzed with Southern blot analysis, but hybridizing D N A was not

Emission of biosynthesized monoterpenes from needles of Norway Spruce

Abstract: 19 th G6ttingen Neurobiol. Conf., p. 38 (N. Elsner, H. Penzlin, eds.). Stuttgart: Thieme 1991 2. Budelmann, B.-U., in: The Mechanosensory Lateral Line. Neurobiology and Evolution, p. 607 (S. Coombs, R Gtirner, H. Mtinz, eds.). New York: Springer 1989 3. Del Pozo, E., Baeyens, J. M.: Eur. J. Pharmacol. 128, 49 (1986) 4. Golz, R., Thurm, U.: Cell Tissue Res. 263, 573 (1991) 5. Holstein, T., Hausmann, K., in: The Biology of Nematocysts, p. 53 (D. A. Hessinger, H. M. Lenhoff, eds.). New York: Academic Press 1988 6. Holstein, T., Tardent, E: Science 223, 830 (1984) 7. Howard, J., Roberts, W. M., Hudspeth, A. J.: Annu. Rev. Biophys. Biophys. Chem. I7, 99 (1988) 8. Kroese, A. B. A., Das, A., Hudspeth, A. J.: Hear. Res. 37, 203 (1989) 9. Lawonn, P., Thurm, U., in: Rhythmogenese in Neuronen und Netzwerken. Proc. 20 th G6ttingen Neurobiol. Conf., p. 557 (N. Elsner, D. Richter, eds.). Stuttgart: Thieme 1992 10. Lenhoff, H. M., in: Hydra: Research Methods, p. 53 (H. M. Lenhoff, ed.). New York: Plenum 1983 11. Mariscal, R. N., in: Coelenterate Biology: Reviews and New Perspectives, p. 129 (L. Muscatine, H. M. Lenhoff, eds.). New York: Academic Press 1974 12. Pantin, C. F. A.: J. Exp. Biol. 19, 294 (1942) 13. Pantin, C. E A., Pantin, A. M. E: ibid. 20, 6 (1943) 14. Prado, W. A., Corrado, A. R, Marseillan, R. E: Arch. Int. Pharmacodyn. 231, 297 (1978) 15. Schacht, J.: Hear. Res. 22, 297 (1986) 16. Slautterback, D. B.: Z. Zellforsch. 79, 296 (1967) 17. Smith, S., Oshida, J., Bode, H.: Biol. Bull. 147, 186 (1974) 18. Thurm, U., Lawonn, E: Verh. Dtsch. Zool. Ges. 83, 431 (1990) 19. Watson, G. M., Hessinger, D. A.: Exp. Cell Res. 198, 8 (1992) 20. Wilby, O. K.: Nature 262, 387 (1976) 21. Zenner, H. E, Gitter, A. H.: Laryngol. Rhinol. Otol. 68, 552 (1989) 22. Zimmermann, U.: Biochim. Biophys. Acta 694, 227 (1982)

To deal with the „Invisible”

Abstract: In the last two decades ultraviolet (UV) sensitivity was demonstrated for a number of bird species [1-3] although we do not know its function in communication and behavior [4, 5]. Objects which are important for many birds, such as the plumage of other birds [6, 7], or fruits, berries [8] and insects [9], often possess UV reflection patterns. The brightly colored passeriform bird Leiothrix Iutea (Timaliidae) is highly sensitive in the UV with a sensitivity peak at 370 nm [10, 11]. Male and female Leiothrix cannot be distinguished b y humans on the basis of their plumage colors. Certain plumage colors exhibit an additional relatively high UV reflection, mainly ,,yellow\" (reflection peak with maximum wavelength at 370 nm) and ,,white\". In the present work it was investigated if remales of Leiothrix actually use UV patterns to discriminate between differently ,,UV-colored\" males. In a behavioral test females of this species could choose between males which differed in their UV reflection. Males seen through a UVtransmitting Plexiglass pane were significantly preferred over males seen through a UV-absorbing Plexiglass pane. The significance was shown both in the number of visits and the time spent with the UV male. This is the first evidence that UV reflection plays a communicative role in a bird's behavior. The selective manipulation of the UV reflection in the bird's plumage is a great problem: Paints with an identical hue in the ,,visible\" and a difference only in the UV are difficult to find. Since birds tend their plumage very carefully, it is neces-

Evolution of eusociality in the Bathyergidae. The case of the giant mole rats (Cryptomys mechowi).

Abstract: Eguchi, E.: J. Exp. Biol. 123, 1 (1986) 11. Hariyama, T., Tsukahara, Y.: Comp. Biochem. Physiol. 91A, 529 (1988) 12. Hariyama, T., Tsukahara, Y.: J. Exp. Biol. (in press) 13. Cronin, T. W., Marshall, N. J.: J. • Comp. Physiol. A 166, 261 (1989) 14. Cronin, T. W.: ibid. 164, 737 (1989) 15. Smith, K. C., Macagno, E. R.: ibid. 166, 597 (1990) 16. Frisch, K. yon: Zool. Jb. 35, 1 (1914) 17. Crescitelli, E: J. Comp. Physiol. A 157, 323 (1985) 18. Peitsch, D., et. al. : ibid. 170, 23 (1992) 19. Meyer-Rochow, V. B.: ibid. 139, 261 (1980)

Cuticular Hydrocarbon Profiles in the Slave-Making Ant Harpagoxenus sublaevis and Its Hosts

Abstract: Although the sex pheromone of the former was estimated to be 100% (+)dispalure, the gypsy moth possesses cells specialized to (+)and (-)-dispalure (a pheromone inhibitor), whereas in the nun moth, which was estimated to utilize 90% (-)-, and 10% (+)-dispalure, both cells responded to (+)-dispalure and no (-)-dispalure-sensitive cell was found. We are grateful to K. Asaoka, Dr. A. Sen, and Dr. J. Inouchi for advice regarding the preparations of samples for SEM and TEM as well as for their critical review of the manuscript. We thank Nitto Electric Co. for providing the synthetic S-enantiomer.

Enantiomer separation of atropisomeric polychlorinated biphenyls (PCBs) by gas chromatography on Chirasil-Dex

Abstract: Eingegangen 21. Juli1992 1. Grimmer, A. R.: Nuclear Magnetic Shielding und Molecular Structure, p. 191 (J. A. Tossel, ed.). Dordrecht: Kluwet 1993 2. Grimmer, A. R., Radeglia, R. : Chem. Phys. Lett. 106, 262 (1984) 3. M6bs, M., Jansen, M.: Z. anorg, allg. Chem. 514, 39 (1984) 4. Mijlhoff, F. C., Portheine, J., Romers, R. : Rec. Tray. Chim. Pays-Bas 86(3), 257 (1967) 5. Frick, F., Jansen, M., Bruna, P. J., Peyerimhoff, S. D. : Chem. Ber. 124, 1711 (1991) 6. Frick, E, Jansen, M.: Z. anorg, allg. Chem. 619, 281 (1993) 7. Herzfeld, J., Berger, A.: J. Chem. Phys. 73, 6021 (1980) 8. Grimmer, A. R., Miiller, D. : Z. Chem. 16, 496 (1976) 9. Schindler, M., Kutzelnigg, W.: J. Chem. Phys. 76, 1919 (1982); die IGLO-Methode ist eine ab-initioMethode zur Berechnung der kernmagnetischen Abschirmung und der magnetischen Suszeptibilit~tt yon Molekfilen. 10. Kutzelnigg, W., Fleischer, U., Schindler, M.: NMR-Basic-Principles and Progress 23, 165 (1990); die IGLORechnungen basieren auf den experimentellen Molektilgeometrien (jeweils zu rid, C3v bzw. C2v symmetrisiert); es wurde die Basis II (beschrieben in [10]) benutzt. 11. Grimmer, A. R. : Dissertation B, Akademie der Wissenschaften, Berlin 1989

Biotransformation of brominated compounds in the marine spongeVerongia aerophoba — Evidence for an induced chemical defense?

Abstract: Over the past 20 years marine secondary products have attracted growing interest due to uniqu e chemical features which, for example, frequently include halogen substituents (very rare in secondary products from terrestrial sources [1]) as well as due to pronounced biological activities which suggest potential value as primary structures for the development of new pharmaceuticals [2]. Sessile marine invertebrates, such as sponges (Porifera), have so far yielded the largest number of bioactive secondary metabolites [3]. Sponges of the order Verongida are rich sources of brominated secondary compounds such as 1-5 (Fig. 1), which are biogenetically thought to be derived from dibromotyrosine [4]. The Mediterranean sponge Verongia aerophoba Schmidt, which is also found around the Canary islands, is exceptionally rich in brominated compounds [5]. We could now show for the first time that the bioactive sponge constituents aeroplysinin-I (4) and the dienone 5 are biotransformation products which originate from the biologically inactive or weakly active precursors isofistularin-3 (1) and aerophobin-2 (3) by enzymatically catalyzed conversions following breakdown of the cellular compartmentation. A stepwise biotransformation of isofistularin-3 (i) and of aerophobin-2 (3) to the dienone 5 via fistularin-1 (2) (only in case of 1) and aeroplysinin-1 (4) as intermediates (Fig. 1) was revealed upon extraction of freeze-dried tissue of V. aerophoba in either 100% MeOH, 50 % aqueous MeOH, or in 100 % H20 as suggested by HPLC analysis of the respective extracts (Fig. 2). 1 and 3 are the dominating brominated constituents in the 100 % MeOH extract of V. aerophoba. The 50% aqueous MeOH extract is characterized by increasing amounts of 2, 4, and 5 (these compounds are almost completely missing in the MeOH extract), whereas both 3 as well as 1 decrease in comparison to the MeOH extract (Fig. 2). In the water extract 5 is detected as the dominating brominated compound along with traces of I (similar results were obtained upon

Juvenility and resistance of a superoxide tolerant plant to diseases and other stresses

Abstract: Manual 1, 5.60. New York: Cold Spring Harbor Lab. Press 1989 10. Maniatis, T., Fritsch, E. E, Sambrook, J. : ibid., 1, 5.72. 11. Murashige, T., Skoog, E: Physiol. Plant 15, 473 (1962) 12. Uchimiya, H., Handa, T., Brar, D. S. : J. Biotech. 12, 1 (1989) 13. Anzai, H., Yoneyama, K., Yamaguchi, I. : Mol. Gen. Genet. 219, 492 (1989) 14. Broglie, K., Chet, I., Holliday, M., Cressman, R., Biddle, R, Knowlton, S., Mauvais, J., Broglie, R.: Science 254, 1194 (1991) 15. Logemann, J., Jach, G., Tommerup, H., Mundy, J., Schell, J.: Biotechnology 10, 305 (1992) 16. Abel, R E, Nelson, R. S., De, B., Hoffmann, N., Rogers, S. G., Fraley, R. T., Beachy, R. N. : Science 323, 738 (1986) 17. Edward K., Cramer, C. L., Bolwell, G. P., Dixon, R. A., Schuch, E., Lamb, C. P.: Proc. Nat. Acad. Sci. USA 82, 6731 (1985)

Evidence for two distinct movement-detecting mechanisms in insect vision

Abstract: terns could contribute to synchronization of the stridulatory and ventilatory rhythms. Furthermore, induced changes in the neuronal discharge modulate stridulation and the coupled abdominal expiratory movement or even bring the song to an end. The effects of such a neuron would be enhanced during the song, owing to the increase in its spike activity, and by the simultaneous action of all the neurons in this class. Given that spiking of the A neurons (in G. bimaculatus) is also suppressed during walking [18], it is conceivable that a function of the SD-AE neurons is to influence motor activities in general. Possibly, the class of SD-AE neurons also exists in grasshoppers [19] and is of overall importance.

Strepsipteran forewings are haltere-like organs of equilibrium

Abstract: The forewings of male Strepsiptera share striking morphological similarities with the hindwing-derived halteres of flies [1-3] that are known to be gyroscopic organs of equilibrium [4-6]. In a combined study of functional morphology and behavior we show for the first time conclusively that the specialized forewings in male Strepsiptera play the same role as halteres in flies. Rotational movements of the animal produce Coriolis forces at the rapidly oscillating clubshaped forewings. These forces are presumably sensed by two fields of campaniform sensilla on the forewings and their signals mediate compensatory movements of head and abdomen. Strepsiptera are an enigmatic group of insect parasites with a large variety of insect hosts. They are thought to be most closely related to Coleoptera [7]. In most cases, females lack wings, legs, and eyes and stay resident in the host throughout their life while males emerge from their puparium to spend about one hour's life on the wing searching for hosts that carry receptive females. The forewings of male Strepsiptera are modified to a dorsoventrally flattened stalk with a distal club [2] (Fig. l a). Two fields of 70-100 campaniform sensilla each are located dorsally and ventrally just distal to the forewings' articulation on the thorax [2] (Fig. lb ) . They send a remarkably thick nerve bundle to the thoracic ganglion [2]. Following Buddenbrock's theory of haltere function [8], Ulrich [2] considered the strepsipteran forewings to play a purely stimulatory role. Experimental tests have never been carried out, however, probably because collecting and handling these tiny, short-lived animals is extremely difficult. In the last few decades it has become well established that the halteres of flies are sense organs with a function analogous to the vestibular organs of vertebrates, crabs, and cephalopods. Rotations of a fly's body generate Coriolis forces perpendicular to the stroke planes

GT dinucleotide repeat polymorphisms in a polygynous ant, Leptothorax spinosior and their use for measurement of relatedness.

Abstract: Polymorphic DNA segments containing GT/AC dinucleotide repeats exist in the genome of the polygynous ant, Leptothorax spinosior Forel. Nucleotide sequences of these segments enabled us to set up primer pairs for amplification of the polymorphic DNA segments by polymerase chain reaction (PCR). The electrophoretic analysis of the amplified DNA revealed a considerable amount of interand intracolonial polymorphisms. In the kin selection theory [1], high relatedness facilitates evolution of eusociality. Polygyny (coexistence of multiple queens) and worker reproduction have raised problems in the evaluation of the relative role of kin selection, as polygyny may lower the relatedness among colony mates [2]. The polygynous ant, L. spinosior lives on flood plains near rivers and about half of the colonies have multiple (2-20) queens in our study field (Hamaguchi et al., unpublished). In polygynous colonies, almost all queens lay eggs, and workers occasionally reproduce. Evaluation of intracolonial relatedness may shed some light on the evolution of polygyny in eusocial insects. Isozyme patterns were used to determine the number of effective egg layers or the intracolonial relatedness of other leptothoracine species [3]. This method, however, cannot be applied to species lacking isozyme polymorphisms. DNA fingerprinting has recently been used successfully to determine parenthood of honeybees [4] and ants (Masuko, pers. comm.). Mitochondrial DNA variation has also been used in L. acervorum to determine the existence of alien queens in a colony [5]. However, DNA fingerprinting may not be applicable to very small insects such as Leptothorax. The mean weight of a worker is 355 ~tg (n = 100) and of a queen 743 btg (n = 5). PCR can detect genetic polymorphisms of one locus basis like isozyme electrophoresis, unlike DNA fingerprinting, with possibly more polymorphisms. This may enable one to extend the method of evaluating relatedness [6] not only to the population mean but to interindividual level. In the present study, we searched for DNA segments containing polymorphic dinucleotide repeats for PCR amplification. Stretches of GT/AC dinucleotide repetitive DNA distributed throughout the genomes of most eukaryotes show a highly polymorphic nature in the number of repeats [7]. DNA was isolated from about 100 worker pupae (43.2 mg) in polygynous colonies kept in the laboratory at Nagoya University. They were homogenized in 0.5 ml of STE (100 mM Tris, 1 M NaC1, 10 mM EDTA, pH 8) and added to 2 ml of STE containing 1% SDS and 200 ~tg of proteinase K. The following procedures were similar to those used to obtain high-molecular DNA. The final estimate of DNA was 29 ~g. The method of searching for DNA sequence candidates for PCR containing GT/AC repeats (digestion of DNA with a restriction enzyme Mbol, purification of 150-350-bp fragments, ligation into plasmid vector pUC 118, colony hybridization, preparation of single-strand DNA, and sequencing) followed procedures of Takenaka et al. [8]. Five out of 104 were positive against (GT)10 probe, which is slightly fewer in frequency than in the chimpanzee [8]. Table 1 summarizes the sequences of ten primer sets, and the theoretical length of

Seasonal variability of Δ15N in settling particles in the Arabian Sea and its palaeogeochemical significance

Abstract: (15N/14N~ [15N/14N~ * ~)15 N = k /Sample --t )Standar~dx 1000 [%0] (15N/]4N)sta.dard cycling in the upper ocean are rapidly transmitted to the deep sea [3]. Therefore, sedimentary 5~5N has the potential to track the history of past changes in nitrogen cycling [4, 5]. We have examined the 6~5N of settling particles collected during an ongoing sediment trap experiment in the Arabian Sea (Fig. 1). This area is influenced by the monsoons and experiences a seasonal reversal in wind direction which is SW in summer (SW monsoon) and NE in winter (NE monsoon) and in its surface circulation pattern [6]. Consequences of the monsoon are high primary productivity associated with upwelling [7] and relatively high river [8] and atmospheric inputs [9]. The region exhibits high rates of N~ fixation [10] and denitriflcation [11] and has been suggested to be a major source of N20 to the atmosphere. Particle fluxes to the deep Arabian Sea have been found the exhibit strong monsoon-related seasonal and interannual variability (Figs. 2, 3) [12, 13]. Peak fluxes occur during the SW and NE monsoons and are in phase with increased surface ocean biological productivity. The western and central Arabian Sea differ from each other in the amount of

Sex pheromone reception in the scarab beetle Anomala cuprea Enantiomeric discrimination by sensilla placodea

Abstract: 1. Kelsey, R. G., Reynolds, G. W., Rodriguez, E., in: Biology and Chemistry of Plant Trichomes, p. 187 (E. Rodriguez, E L. Healey, I. Mehta., eds.). New York: Plenum 1984; Lieutier, E, Cheniclet, C., Garcia: J. Envir. Entotool. 18, 228 (1989); Muller, C. H., in: Recent Advances in Phytochemistry, Vol. 3, p. 105 (C. Steelink, V. C. 2. Runeckles, eds.). New York: AppletonCentury-Crofts 1970; Paster, N., Nuven, B. J., Shaaya, E., Menasherov, M., Nitzan, R., Weisslowicz, H., Ravid, U.: Lett. Appl. Microbiol. 11, 33 (1990); Salmeron, J., Jordano, R., Pozo, R.: J. Food Protec. 53, 697 (1990) Enders, G., Dlugi, R., Steinbrecher, R., Clement, B., Daiber, R., Eijk, J. v., Gab, S., Haziza, M., Helas, G., Herrmann, U., Kessel, M., Kesselmeier, J., Kotzias, D., Kurth, H.-H., McMillen, R. T., Roider, G., Schiirmann, W., Teichmann, U., Torres, L.: Atmos. Environ. 26A, 171 (1992); Rasmussen, R., Went, E: Proc. Nat. Acad. Sci. USA 53, 215 (1965); Zimmermann, E R.: EPA 450/4-79-004 (1979) 3. Arnts, R. R., Petersen, W. B., Seila, R. L., Gay, B. W.: Atmos. Environ. 16, 2127 (1982); Atkinson, R., Aschman, S. M., Pitts Jr., J. N.: J. Phys. Chem. 92, 3454 (1988); Stangl, H., Kotzias, D., Geiss, E: Naturwissenschaften 75, 42 (1988) 4. Cheniclet, C., Carde, J.: Israel J. Bot. 34, 219 (1985); Grumbach, K. H., Forn, B.: Z. Naturforsch. 35c, 645 (1980); Mettal, U., Boland, W., Beyer, E, Kleinig, H.: Eur. J. Biochem. 170, 613 (1988); Schulze-Siebert, D., Schultz, G.: Plant Physiol. Biochem. 25, 145 (1987); Perez, L. M., Pauly, G., Carde, J. R, Belingheri, L., Gleizes, M.: Plant Physiol. Biochem. (Paris) 28, 221 (1990) 5. Bernard-Dagan, C., Carde, J. E, Gleizes, M.: Can. J. Bot. 57, 255 (1979); Gleizes, M., Pauly, G., Carde, J. R, Marpeau, A., Bernard-Dagan, C.: Planta 159, 373 (1983); Jtittner, E, Burlet, U.: Projekt Europgisches Forschungszentrum for MaBnahmen zur Luftreinhaltung (PEF), 4. Statuskolloquium. Kemforschungszentrum Karlsruhe 1988; Sch6nwitz, R., Lohwasser, K., Kloos, M., Ziegler, H.: Trees 4, 34 (1990); Zavarin, E., Cobb, E W., Betgot, J., Barber, H. W.: Phytochemistry 10, 3107 (1971) 6. Foyer, C., Halliwell, B.: Planta 133, 21 (1976) 7. Osmond, C. B., Winter, K., Ziegler, H., in: Encyclopedia of Plant Physiology (NS), Vol. 12B, p. 480 (O. L. Lange, P. S. Nobel, C. B. Osmond, H. Ziegler, eds.). Berlin-Heidelberg-New York: Springer 1982 8. Sch6nwitz, R., Merk, L., Ziegler, H.: Trees 1, 88 (1987)

Involvement of serotonin in the circadian rhythm of an insect visual system

Abstract: Am. A 6, 116 (1989) 9. Hausen, K.: Biol. Cybern. 45, 143 (1982) 10. Quenzer, T., Zanker, J. M. : J. Comp. Physiol. A 169, 331 (1991) 11. Quenzer, T.: Diplomarbeit Univ. Ttibingen 1990 12. Egelhaaf, M., Borst, A.: J. Opt. Soc. Am. A 7, 172 (1990) 13. G6tz, K. G. : Kybernetik 2, 77 (1964) 14. Kunze, E: Z. vergl. Physiol. 44, 656 (1961) 15. Borst, A., Bahde, S. : Biol. Cybern. 56, 217 (1987) 16. Egelhaaf, M., Borst, A., Reichardt, W. :J. Opt. Soc. Am. A 6, 1070 (1989) 17. Laughlin, S. B., in: Handbook of Sensory Physiology, Vol. VII 6B, p. 133 (H. Autrum, ed.). Berlin: Springer 1981 18. Laughlin, S. B., Hardie, R. 'C.: J. Comp. Physiol. 128, 319 (1978)

Retinal image size triggers obstacle avoidance in flying locusts

Abstract: d8 99 + + 335 568 y w 25-w 1-y 1-362 568 meiotic recombination between the two Y's can practically be excluded; it lies definitely under 2 %. The possibility of X-Y recombination in female meiosis has also been tested. The 362 male offspring of In(1)sc4LscSR,y sc4scSw/In(1)sc 4L scSR,y sc4scSw/w+W y+ $ 9 x wild-type d d showed the expected genotypes (Fig. 2, Table 4) with the exception of two recombinants that, again, most probably result from exchange between one of the X's and a euchromatic section within the w+Y y+ chromosome. Mitotic recombination has been induced by treating larvae 42-44 h after egg deposition with X-rays (100 kV, 8 mA, FD 10 cm, 1.7 mm Al-filter, exposure time 1.5 rain, corresponding to 1480 _+ 20 R); or with mitomycin C (1.5 ml 1.2 mM mitomycin C in 0.5 % saccharose solution, 2.5 h feeding time). Three days after hatching adults were inspected for single and twin mosaic spots in their eyes. Control recombination frequencies depend upon the distance between cen-tromere and marker, in our case almost the whole length of the X-chromosome; they lie below 0.5 % [1]. On the y+Y map chromosome see [7, 8], on zeste see [4].

Magnetic orientation in the fire ant,Solenopsis invicta

Abstract: 1. Kudo, R.R.: Protozoology. Springfield, Ill.: Thomas 1954 2. Harland, W.B., Armstrong, R.L., Cox, A.V., Craig, L.E., Smith, A.G., Smith D.G.: A Geological Time Scale 1989. Cambridge: Cambridge Univ. Press 1989 3. Maxwell, R.D.: Introduction to Protozoology. New York: St. Martin's Press 1961 4. Smith, G.M.: The Fresh-water Algae of the United States. New York: McGrawHill 1933 5. Tappan, H.: The Paleobiology of Plant Protists. San Francisco: Freeman 1980 6. Poinar, Jr., G.O., Waggoner, B.M., Bauer, U.C.: Science 259, 222 (1993) 7. Thiessen, R., Sprunk, G.C.: U.S. Dept. Interior Tech. Pap. No. 631, p. 1 (1941) 8. Glaessner, M.E: The Dawn of Animal Life: A Biohistorical Study. Cambridge: Cambridge Univ. Press 1984 9. Schuster, EL., in: Handbook of Protoctista (L. Margulis, J.O. Corliss, M. Melkonian, D.J. Chapman, eds.). Boston: Jones and Bartlett 1989 10. Clark, C.G., Gross, G.A.M.: Mol. Biol. Evol. 5, 512 (1988) 11. Christen, R., Ratto, A., Baroin, A., Perasso, R., Grell, K.G., Adoutte, A.: EMBO J. 10, 499 (1991) 12. Allison, C.W., Hilgert, J.W.: J. Paleontol. 60, 973 (1986) 13. Pokorny, V.: Principles of Zoological Micropaleontology. New York: Macmillan 1963 14. Loeblich, A.R., Tappan, H., in: Treatise on Invertebrate Paleontology C(2), Vol. 1. (R.C. Moore, ed.). Lawrence: Geol. Soc. of America and Univ. of Kansas Press 1964 15. Waggoner, B.M.: J. Protozool. 40, 98 (1993) 16. Waggoner, B.M.: PaleoBios (in press)

Identification of the sex pheromone of an ant, Formica lugubris (Hymenoptera, Formicidae)

Abstract: 1. Schulten, H.-R., Plage, B., Schnitzer, M. : Naturwissenschaften 78, 311 (1991) 2. Haworth, R. D. : Soil Sci. 11I, 71 (1971) 3. Roulet, N., Mehta, N. C., Dubach, E, Denel, H.: Z. Pflanzenern~ihr. Dfing. Bodenk. 103, 1 (1963) 4. Sowden, F. J., Schnitzer, M. : Can. J. Soil Sci. 47, 111 (1967) 5. Khan, S. U., Sowden, F. J. : ibid. 5/, 185 (1971) 6. Lowe, L. E., in: Soil Organic Matter, p. 65 (M. Schnitzel S. U. Khan, eds.). Amsterdam: Elsevier 1978 7. Schulten, H.-R., Schnitzer, M.: Soil Sci. 153, 205 (1992) 8. Schulten, H.-R., Schnitzer, M.: Sci. Total Environ. 117/118, 27 (1992) 9. Schnitzer, M., Kodama, H., Ripmeester, J. A. : Soil Sci. Soc. Am. J. 55, 745 (1991) 10. Schnitzer, M., in: Soil Organic Matter, p. 1 (M. Schnitzer, S. U. Khan, eds.). Amsterdam: Elsevier 1978 11. Hansen, E. H., Schnitzer, M. : Soil Sci. Soc. Am. Proc. 30, 745 (1966) 12. Hansen, E. H., Schnitzer, M. : ibid. 33, 75 (1969) 13. Gosh, K., Schnitzer, M.: Soil Sci. 129, 266 (1980) 14. Stevenson, I. L., Schuitzer, M.: ibid. 133, 179 (1982)

Paternity analysis of worker honeybees using random amplified polymorphic DNA

Abstract: Acad. Sci. USA 86, 3252 (1989); Miceli, C., La Terza, A., Melli, M.: ibid. 86, 3016 (1989) 6. Meyer, F., Schmidt, H. J., Pliimper, E., Hasilik, A., Mersmann, G., Meyer, H. E., Engstr6m, A., Heckmann, K.: ibid. 88, 3758 (1991) 7. Meyer, F., Schmidt, H. J., Heckmann, K.: Dev. Genet. 13, 16 (1992); Heckmann, K.: Verh. Dtsch. Zool. Ges. 85, 185 (1992) 8. Greenwood, S. J., Schlegel, M., Sogin, M., Lynn, D. H.: J. Protozool. 38, 1 (1991) 9. Barahona, I., Soares, H., Cyrne, L., Penque, D., Denoulet, E, RodriquesPousada, C.: J. Mol. Biol. 202, 365 (1988); Little, M., Seehaus, T.: Comp. Biochem. Physiol. 90B, 655 (1988) 10. Sanger, E, Nicklen, S., Coulson, A. R.: Proc. Nat. Acad. Sci. USA 74, 5463 (1977) 11. Liang, A.: Dissertation Univ. Miinster 1992 12. Helftenbein, E., Mtiller, E.: Curt. Genet. 13, 425 (1988); Gaunitz, E: Dissertation Univ. Ttibingen 1990 13. Fleury, A.: BioSystems 21, 309 (1988) 14. Osawa, S., Jukes, T. H., Watanabe, K., Muto, A.: Microbiol. Rev. 56, 229 (1992) 15. B6ck, A., Forchhammer, K., Heider, J., Baron, C.: TIBS 16, 463 (1991)

Discovery of a new vanadium accumulator, the fan worm Pseudopotamilla occelata

Abstract: Many biologists, physiologists, and chemists have been interested in the significance of high vanadium concentrations in ascidians since the first report on its accumulation by Henze in 1911 [1]. In spite of many efforts to find other vanadium accumulators for a comparative study, it has been thought that only ascidians in the Animal Kingdom have the special ability to accumulate vanadium at a high level. During our screening work on elemental concentrations in marine organisms collected from the sea

Phanerozoic patterns of marine CaCO3 precipitation

Abstract: the Arabian Sea glacial sediments to be 6-9%0. The corresponding Holocene values are 9-12%o and suggest less intense water-column denitrification in the glacial Arabian Sea and possibly in low-latitude oceans in general. In anal- ogy to the suggested reduction in shelf denitrification during the glacial [20], lower water-column denitrification could have increased nitrogen availability for primary productivity in low-latitude oceans. Supported by the Federal German Ministry for Research and Technology (BMFT, Bonn) within the framework of a joint Indo-German Marine Science Project. Received Juli 26, 1993 1. Wada, E., Hattori, A. : Geomicrobiol. J. 1, 85 (1978); Montoya, J. R: Thesis Harvard Univ. 1990 2. Wada, E., in: Isotope Marine Chemis- try, p. 375 (E. D. Goldberg, Y. Horibe, K. Saruhashi, eds.). Tokyo: Uchida Rokakuho 1980 3. Altabet, M. A., Deuser, W. G. : Nature

Control of interspecific relationships in marine ciliate protists by most evolved natural products

Abstract: Dipartimento di Scienze dell 'Ambiente e del Territorio, Sezione di Protistologia, Universith di Pisa, 1-56100 Pisa Istituto di Chimica, Universit~ di Trento, 1-38050 Povo-Trento tures by centrifugation, EtOH-extracted, and subjected to CN HPLC (7 ~m, 20×1 cm, 98:2 hexane/isopropanol, 5 ml/min) giving euplotin A 1 (I) and 132 (2) (Fig. 1) in 4.1/1 weight ratio. These substances were not found, at the sensitivity level of HPLC-UV, in the cell-free culture medium (recovered from 3-day-starved mass cultures) where they, despite insolubility in neat

Reflection-Polarization pattern at water surfaces and correction of a common representation of the polarization pattern of the sky

Abstract: Many hydrophilous insects recognize water by the polarization of the reflected light [1]. When the water is illuminated by diffuse, nonpolarized sky light, the animals have a relatively simple polarization pattern to identify: all the e vectors in the reflected light are horizontal. But when the sky is clear and visibility good, very complicated polarization patterns can develop due to superposition of the polarization characteristics of the water surface and the partially reflected polarization pattern of the sky light. We have calculated such patterns for an ideal water surface, and present them here. We also present a revised picture of the polarization of sky light. The drawing of the sky polarization pattern published in 1959 by Stockhammer [2], which has been reproduced in many review articles and textbooks (e.g. [3-6]), and the two-dimensional representation of the sky polarization pattern published by Wehner [7,8] contain an error in the directions of the e vectors. Here we correct this error. For the calculations of reflection polarization the sky polarization pattern was slightly idealized; the lines of equal polarization were assumed to form exact circles around the position of the sun, as in Wehner's [9] three-dimensional polarization pattern, and the e vectors were assumed to be exactly aligned with these circles. Departures from this regular pattern in the vicinity of the sun (Babinet and Brewster neutral point) were disregarded. These departures are negligible because here the stronger polarization of the water surface predominates. The degree of polarization was approximated by d = dmax-Sin 2 cd(l+cos2c0 (see [10], p. 288; a is the angular distance from the sun). For sun elevations of 0 ° (sun at the horizon), 30 ° , 60 ° , and 90 ° , dma~ was taken to be 77, 70, 63, and 56%, respectively (see [10], p. 295). To calculate the reflection of the sky polarization pattern the appropriate Fresnel formulas were used ([11], p. 332). With an ideal water surface under diffuse, unpolarized sky light, all the e vectors in the reflection-polarization pattern are arranged concentrically around the center of the pattern; that is, from the viewpoint of an observer they appear horizontal (Fig. la). Polarization is maximal at the Brewster angle 0 = 5 3 ° (dotted line representing a degree of polarization d=100 %). The relative intensity of the reflected light is not shown in the figures. For unpolarized incident light it is 2% at ®=0 ° (in the center of the pattern) and 7.6 % at the Brewster angle; the amount of light reflected rises rapidly for ® > 60 °, reaching 100 % at ®=90 ° (at the edge of the pattern). With a clear, cloudless sky the polarization pattern visible over the water surface is considerably more complicated, because the polarization pattern of the sky itself contributes, to some extent,