Interspezifische Transformationen zwischen Agrobacterium tumefaciens und Rhizobium leguminosarum

Zusammenfassung Als weiterer Beweis für die Transformierbarkeit von Agrobacterium tumefaciens und Rhizobium leguminosarum werden wechselseitige Transformationsversuche durchgeführt und dabei die Resistenz gegen Streptomycin bzw. gegen ein Sulfonamid (Marbadal) als Selektionsmaterial benutzt. Die ermittelten Transformationsraten liegen in der Größenordnung von 4–7 · 10^-6 bzw. 13 bis 16 · 10^-6.

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Interspecific transformations of Agrobacterium tumefaciens and Rhizobium leguminosarum

Summary As further proof for the transformability of Agrobacterium tumefaciens and Rhizobium leguminosarum reciprocal transformation assays were performed using the resistence against streptomycin resp. against a sulfonamide (Marbadal) as selection marker. The transformations rates are 4–7×10^-6 resp. 13–16×10^-6.

     

Die wachstumsfördernde Wirkung von Tannin auf Getreidekoleoptilen

Zusammenfassung Schwach konzentrierte Tanninlösungen (5·10^–5 bis 5·10^–8 molar) vermochten das Wachstum 10 mm langer Koleoptilabschnitte von 15 Kulturformen vonAvena sativa, Hordeum distichon, Hordeum vulgare, Zea mays, Triticum aestivum undSecale cereale um etwa 6–25% zu fördern. Die mögliche Beteiligung von Gerbstoffen am Streckungswachstum höherer Pflanzen wurde diskutiert.

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Summary The growth of 10 mm coleoptile sections of 15 cultivars ofAvena sativa, Hordeum distichon, Hordeum vulgare, Zea mays, Triticum aestivum andSecale cereale was stimulated by dilute tannin-solutions (5·10^–5 to 5·10^–8 molar) from 6 up to 25%. The possible role of tannins in elongation growth of higher plants was discussed.

     

Postsynaptic effects of substance P in frog neuromuscular junction

We have studied the effect of substance P on the end-plate currents (EPC) and the miniature EPC (MEPC) after acetylcholine esterase (ACE) inhibition in the cut neuromuscular preparation of the frog sartorius muscle using the voltage-clamp technique. At concentrations of 5·10^–7–1·10^–6 moles/liter substance P had no effect on the amplitude and the time characteristics of single EPC and MEPC but promoted prolongation of EPC decay on repetitive stimulation of the nerve with a frequency of 10/sec, indicating intensification of postsynaptic potentiation. Elevation of the concentration of the given peptide to 5·10^–6 moles/liter led to the shortening of the decay of single EPC and a more marked depression of the EPC amplitude in the trains as compared to the control, reflecting a decrease in the sensitivity of the postsynaptic membrane to the mediator, i.e., development of desensitization.S. V. Kurashov State Medical Institute, Kazan. I. M. Sechenov Institute of Evolutionary Physiology and Biochemistry, Leningrad. Translated from Neirofiziologiya, Vol. 23, No. 4, pp. 436–441, July–August, 1991.     

Phase transitions and thermal expansion coefficients of plant cuticles

The temperature-induced volume expansion of enzymatically isolated cuticular membranes of twelve plant species was measured. All cuticular membranes exhibited distinct second-order phase transitions in the temperature range of about 40 to 50° C. Increases in the volumes of fruit cuticles (Lycopersicon, Cucumis, Capsicum, Solanum and Malus) were fully reversible, while leaf cuticular membranes (Ficus, Hedera, Nerium, Olea, Pyrus, Picea and Citrus) underwent irreversible structural changes. Below the phase-transition temperature, volumetric expansion coefficients ranged from 0.39·10^–6 m³·kg^–1·K^–1 to 0.62·10^–6 m³·kg^–1·K^–1, and above from 0.60·10⁶ m³·kg^–1·K^\-1 to 1.41· 10^–6 m³·kg^–1·K^–1. Densities of cuticles at 25° C ranged from 1020 kg·m^–3 to 1370 kg·m^–3. Expansion coefficients and phase transitions were characteristic properties of the polymer matrix as a composite material, rather than of cutin alone. It is argued that the sudden increase of water permeability above the transition temperature, is caused by an increase of disorder at the interface between the polymer matrix and the soluble cuticular lipids. Possible ecological and physiological consequences of these results for living plants are discussed.Abbreviations CM Cuticular membrane - CU cutin - MX polymer matrix - SCL soluble cuticular lipids (waxes) The authors greatfully acknowledge stimulating discussions with Drs. H. Gruler (Exp. Physik 3, Universität Ulm, FRG) and M. Riederer (Institut für Botanik und Mikrobiologie, Technische Universität München, München, FRG) and financial support by the Deutsche Forschungsgemeinschaft.     

Medium optimization for a methanol utilizing bacterium based on chemostat theory

Summary In the productions of biomass and vitamin B₁₂ using methanol as the sole carbon source, it is necessary to use a medium in which methanol is the growth limiting substrate. Other inorganic salts should be in slight excess so that the yield of cells and the intracellular content of vitamin B₁₂ do not vary. From basic principles of chemostat culture, a medium was optimized for Pseudomonas AM-1 a methanol utilizing bacterium, for the concentrations of various inorganic salts. This was done in a series of chemostat cultures at a dilution rate of 0.1 h^–1. Optimum amounts of NH₄ ⁺, PO₄ ^3- and Mg²⁺ were estimated from the minimum concentration of the salt at which methanol became growth limiting. The optimum concentrations of Ca²⁺, Fe²⁺, Mn²⁺, and Zn²⁺ as a group were determined in the same way. Cu²⁺, Mo⁶⁺, Co²⁺ and B³⁺ are required at concentrations of g/l and they were not studied as these very low level can be introduced as contaminants from other salts. The optimum medium composition (in g/l) was as follows: (NH₄)₂SO₄, 1.0; H₃PO₄, 75×10^–3; MgSO₄ · 7H₂O, 30×10^–3; CaCl₂ · 2H₂O, 3.3×10^–3; FeSO₄ · 7H₂O, 1.3×10^–3, MnSO₄ · 4H₂O, 0.13×10^–3; ZnSO₄ · 7H₂O, 0.13×10^–3; CuSO₄ · 5H₂O, 40×10^–6; Na₂MoO₄, 40×10^–6; CoCl₂ · 6H₂O, 40×10^–6; H₃BO₃, 30×10^–6 and methanol 4.     

Effects of prolonged cycle ergometer exercise on maximal muscle power and oxygen uptake in humans

The mechanical power (W_tot, W·kg^–1) developed during ten revolutions of all-out periods of cycle ergometer exercise (4–9 s) was measured every 5–6 min in six subjects from rest or from a baseline of constant aerobic exercise [50%–80% of maximal oxygen uptake (VO_2max)] of 20–40 min duration. The oxygen uptake [VO₂ (W·kg^–1, 1 ml O₂ = 20.9 J)] and venous blood lactate concentration ([la]_b, mM) were also measured every 15 s and 2 min, respectively. During the first all-out period, W_tot decreased linearly with the intensity of the priming exercise (W_tot = 11.9–0.25·VO₂). After the first all-out period (i greater than 5–6 min), and if the exercise intensity was less than 60% VO_2max, W_tot, VO₂ and [la]_b remained constant until the end of the exercise. For exercise intensities greater than 60% VO_2max, VO₂ and [la]_b showed continuous upward drifts and W_tot continued decreasing. Under these conditions, the rate of decrease of W_tot was linearly related to the rate of increase of V [(d W_tot/dt) (W·kg^–1·s^–1) = 5.0·10^–5 –0.20·(d VO₂/dt) (W·kg^–1·s^–1)] and this was linearly related to the rate of increase of [la]_b [(d VO₂/dt) (W·kg^–1·s^–1) = 2.310^–4 + 5.910^–5·(d [la]_b/dt) (mM·s^–1)]. These findings would suggest that the decrease of W_tot during the first all-out period was due to the decay of phosphocreatine concentration in the exercising muscles occurring at the onset of exercise and the slow drifts of VO₂ (upwards) and of W_tot (downwards) during intense exercise at constant W_tot could be attributed to the continuous accumulation of lactate in the blood (and in the working muscles).     

Nitrite uptake by Chlamydomonas reinhardtii cells immobilized in calcium alginate

When an initial cell loading of about 30–40 µg chlorophyll (Chl)·g^–1 gel and alginate suspension of 3% (w/v) were used for immobilization of Chlamydomonas reinhardtii, the resulting cell beads showed optimum nitrite uptake rate, at 30° C and pH 7.5, of 14 µmol NO _inf2 ^sup– ·mg^–1 Chl·h^–1, the photosynthetic and respiratory activities being about 120 µmol O₂ produced·mg^–1 Chl·h^–1, and 40 µmol O₂ consumed ·mg^–1 Chl·h^–1, respectively. The nitrite uptake activity required CO₂ in the culture and persisted after 8 days of cells immobilization, or in the presence of 0.2 mm ammonium in the medium. Our data indicate that alginate-entrapped C, reinhardtii cells may provide a stable and functional system for removing nitrogenous contaminants from waste-waters.Correspondence to: C. Vílchez     

Compartmentation of fluorescent tracers injected into the epidermal cells of Egeria densa leaves

We have compared the movement of a series of fluorescent tracers of increasing molecular weight injected into the cytoplasm in the epidermal cells of leaves of Egeria densa Planch. In general, the tracers showed major movement into three cellular compartments: first, to the cytoplasm of adjacent cells; secondly, from the cytoplasm, to the vacuole (irreversible); and thirdly, from the cytoplasm to the nucleus (reversible). No visible accumulation in chloroplasts or mitochondria, or loss across the plasmalemma was observed. No evidence for metabolic breakdown was found in extracts from injected leaves. The time course of accumulation of the dye in the three major compartments (cytoplasm, nucleus, vacuole) was monitored using fluorescence microscopy. The rate measurements and the quantified geometry of the cells were used to generate a model of compartmentation during intercellular transport. Permeability coefficients were calculated and related to the molecular sizes of the tracers. The coefficients for the tonoplast and nuclear envelope were independent of the molecular sizes of the tracers, and were in the range 2.4·10^–6–4.1· 10^–6 cm·s^–1 for the tonoplast, and 2.6·10^–5-9.4.10^–5 cm· s^–1 for the nuclear envelope. For intercellular movement, permeabilities were strongly dependent on molecular size, and ranged from 1.1·10^–4 cm·s^–1 for 6-carboxyfluorescein (376 daltons (Da)) to 9·10^–9 cm·s^–1 for fluorescein leucyldiglutamylleucine (874 Da). Thus, the differences in cell-to-cell movement of these tracers are based upon their differing ability to cross the intercellular walls, not upon differences in their intracellular compartmentation.Abbreviations 6COOHF 6-Carboxyfluorescein - Da daltons - DAPI 4,6-diamidino-2-phenylindole - F fluorescein-isothiocyanate isomer I - FGlu fluorescein glutamic acid - F(Glu)₂ fluorescein glutamyl-glutamic acid - F(Gly)₆ fluorescein hexaglycine - FLGGL fluorescein leucyl diglutamyl-leucine This work was supported by the Australian Research Grant Scheme. The assistance of Professor B.E.S. Gunning (Australian National University, Canberra, ACT) in providing facilities for making the photometer measurements is gratefully acknowledged.     

Untersuchungen an Regio olfactoria und Nervus olfactorius der Silbermöve (Larus argentatus)

Zusammenfassung Nach Perfusionsfixierung mit Glutaraldehyd und anschließender Nachfixierung mit OsO₄ erscheint die Regio olfactoria vom Vogel (Larus argentatus) in Alkohol bei schräg einfallendem Licht in einer goldbraunen Interferenzfarbe. Sie ist von der blaugrünen Regio respiratoria scharf abgegrenzt und bedeckt in einer Nasenhälfte 71 mm². Unter der Stereolupe ist ein fellartiges Faserwerk der oberflächlich ausgerichteten Riechgeißelbündel erkennbar. Der olfaktorische Saum ist in zwei funktionell-morphologische Zonen unterteilt. 1. In eine Innenzone, die die Riechkolben und die Mikrozotten der Stützzellen beherbergt und von der intervillösen Schleimschicht erfüllt wird. 2. In eine Außenzone, die aus der Schicht der oberflächlich ausgebreiteten Riechgeißeln und dem sie bedeckenden Terminalfilm gebildet wird. Als Produkt der Bowmanschen Drüsen ist der Terminalfilm mit osmiophilen Sekrettropfen versehen, die sich in ihm auflösen oder zu einem 500 Å feinen, osmiophilen Oberflächenfilm zerfließen. Durch positive PAS-Reaktionen konnte der Mucopolysaccharidgehalt beider Schleimschichten nachgewiesen werden.Die Riechkolben der Vögel erfahren durch etwa 200 Mikrovilli eine Oberflächenvergrößerung um rund 800% und sind mit 7–13 Riechgeißeln versehen, deren Länge 90–130 . beträgt. Das 9+2-Fibrillenmuster der 20–30 langen proximalen Geißelabschnitte geht in den 60–100 langen distalen Segmenten in eine regellose Formation von 8–16 Tubuli über, die in einer kurzen Endzuspitzung auf 2–6 abnehmen. Die von den Riechkolben zentralwärts ziehenden Mikrotubuli nehmen von anfänglich 270–210 im Sinnesfortsatz kontinuierlich an Zahl ab, um sich im apikal vom Kern gelegenen Golgiapparat zu verlieren. Außer durch Schleimpakete ist das Stützzellplasma durch knäuelförmige Endoplasmaformationen mit konzentrisch geschichteten Endoplasmaspalten charakterisiert.Der Axongehalt des rechten Riechnerven eines jungen Männchens vonLarus argentatus beträgt 3,7·10⁶, der eines alten Weibchens 2,9·10⁶; man kann auf eine Gesamtzahl der Riechrezeptoren von 7,4·10⁶ und 5,8·10⁶ schließen. Die Axone verlieren auf ihren Weg von der Lamina propria zum rostralen Riechnervendrittel etwa 2–3 Mikrotubuli. Neben Axonen mit 2–14 Mikrotubuli, die den Riechfaseranteil darstellen, enthält der Riechnerv noch einige Axone mit rund 20 und 40 Tubuli. Diese letztgenannte Gruppe tritt in synaptischen Kontakt mit Ganglienzellen im rostralen Riechnervenviertel. Die Ganglienzellen verkörpern das diffuse Ganglion terminale, dessen Bedeutung für eine nervöse Steuerung der Bowmanschen Drüsen diskutiert wird.Die funktionelle Bedeutung der Rezeptorzotten, des osmiophilen Oberflächenfilmes und der intervillösen Schleimschicht wird erörtert. Der Gehalt der Regio olfactoria der Silbermöve an Riechrezeptoren wird mit bereits vorliegenden Untersuchungen an Makrosmatikern verglichen.

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On the regio olfactoria and nervus olfactorius in the gull,Larus argentatus

Summary After perfusion with glutaraldehyde and subsequent fixation with OsO₄ the regio olfactoria of the gull (Larus argentatus) shows in alcohol with incident illumination a golden-brown interference colour. It is distinctly defined against the bluegreen regio respiratoria and covers in one side of the nasal cavity 71 mm². The olfactory region demonstrates under a magnifier a furlike structure, produced by the superficial bundles of olfactory cilia. The olfactory border can be subdivided into two layers, namely: 1. An inner layer, which contains the olfactory vesicles and microvilli of supporting cells and is covered by the inner mucous layer. 2. An outer layer, which is composed by the zone of the superficially spread olfactory cilia and the covering terminal film. As a product of the Bowman glands the terminal film is supplied with osmiophilic secretion droplets, which dissolve or rise up and flow into a 500 Å thick superficial osmiophilic coating. The contents of mucopolysaccharids of both mucous layers were proved by positive PAS-reaction.The free surface of the avian olfactory vesicle is increased to 800% by about 200 microvilli and has 7–13 olfactory cilia, the length of which measures 90–130 . The 9+2 fibrillar pattern of the 20–30 long proximal segments of the olfactory cilia changes into an irregular formation of 8–16 tubules of the 60–100 long distal segments, which contain in their short endings only 2–6 tubules. The number of microtubules in the sensory processes decreases continuously on the way from the olfactory vesicle to the soma from initially 270–210 until they disappear in the Golgi apparatus, located apical from the nucleus. Apart from copious drops of mucous the supporting cells are characterized by voluminous convolutes of endoplasmatic membranes.Concluding from the contents of axons of the right n. olfactorius of a young male with 3,7·10⁶ and an adult female with 2,9·10⁶ the total number of receptor cells is estimated to amount to 7,4·10⁶ and 5,8·10⁶. From the lamina propria to the distal quarter of the n. olfactorius the axons loose about 2–3 microtubules. In addition to the axons with 2–14 microtubules representing the olfactory nerve fibers the n. olfactorius also consists of some axons with about 20 and 40 tubules. The latter fibers come into synaptic contact with scattered nerve-cells in the distal quarter of the n. olfactorius, apparently forming the ganglion terminale, which probably regulates secretory activities of the Bowman glands.The receptor microvilli, the osmiophilic superficial mucous coating, and the inner mucous layer are discussed in respect to their olfactory function. The quantity of olfactory receptor cells in the Herring Gull is compared with data on macrosmatic animals in earlier investigations.

Unter dankenswerter Anleitung von Prof. Dr. med. K. H. Andres.     

Phosphorus and nitrogen excretion rates of zooplankton from the eutrophic Loosdrecht lakes,with notes on other P sources for phytoplankton requirements

Phosphorus and nitrogen excretion rates by zooplankton communities from two eutrophic and shallow Dutch lakes were measured in laboratory. The variations in excretion rates in the lakes (May–October) were caused mainly by fluctuation in zooplankton biomass. Mean summer excretion rates (June–September) were 2.4 and 0.9 µg PO₄P·1^–1·d^–1 in Lake Loosdercht and Lake Breukeleveen, respectively. This difference between the lakes was caused mainly by the lower zooplankton biomass in Lake Breukeleveen. The excretion of 2.4 µg PO₄P·1^–1·d^– compared with the calculated P-demand of phytoplankton of 8.0 µg PO₄P·1^–1·d^–1 is substantial in the summer (June–September) and far more important than the external P-supply of 0.4 µg P·1^–1·d^–1 and sediment release of 0.5 µg P·1^–1·d^–1. Both temperature and composition of zooplankton affected the weight specific excretion rates of the zooplankton community. The weight specific community excretion rates of P and N increased with temperature (exponential model); 1–8 g PO₄P·mg^–1 zooplankton-C·d^–1 and 5–42 µg NH₃N·mg^–1 zooplankton-C·d^–1 (10°C–20°C).