Showing papers by "University of Konstanz published in 1983"

Studies on dissimilatory sulfate-reducing bacteria that decompose fatty acids

Abstract: Gliding motility, ultrastructure and nutrition of two newly isolated filamentous sulfate-reducing bacteria, strains 5ac10 and 4be13, were investigated. The filaments were always attached to surfaces. Growth was supported by addition of insoluble aluminium phosphate or agar as substrata for gliding movement. Electron microscopy of ultrathin sections revealed cell walls characteristic of Gramnegative bacteria; the undulated structure of the outer membrane may pertain to the translocation mechanism. Intracytoplasmic membranes were present. Acetate, higher fatty acids, succinate or fumarate served as electron donors and carbon sources. Strain 5ac10 grew also with lactate, but not with benzoate that was used only by strain 4be13. Strain 5ac10 was able to grow slowly on H2 plus CO2 or formate in the presence of sulfate without additional organic carbon source. The capacity of complete oxidation was shown by stoichiometric measurements with acetate plus sulfate. Both strains contained b- and c-type cytochromes. Desulfoviridin was detected only in strain 5ac10. The two filamentous gliding sulfate reducers are described as new species of a new genus, Desulfonema limicola and Desulfonema magnum.

Generalized hydrodynamics of systems of Brownian particles

Abstract: A generalized hydrodynamic theory is developed for systems of interacting Brownian particles on the basis of a Fokker-Planck equation General results are derived for correlation functions, frequency- and wave-vector dependent transport coefficients Explicit expressions for moments, cumulants and the hydrodynamic limits of the transport coefficients are given For the special cases of overdamped systems with and without hydrodynamic interaction the general results are simplified As an example for the application of this approach the system of charged spherical polystyrene spheres in aqueous solution is treated in detail The generalized transport functions are evaluated in mode-mode coupling approximation and detailed numerical results are presented for various collective and single-particle properties Finally, the relationship to a corresponding Smoluchowski approach is discussed

Cortical and thalamic afferent connections of the insular and adjacent cortex of the cat

Abstract: Thalamic and cortical afferents to the insular and perirhinal cortex of the rat were investigated. Unilateral injections of horseradish peroxidase (HRP) were made iontophoretically along the rhinal sulcus. HRP injections covered or invaded areas along the rhinal fissure from about the level of the middle cerebral artery to the posterior end of the fissure. The most anterior injection labeled a few cells in the mediodorsal nucleus. More posterior injections labeled neurons in the basal portion of the nucleus ventralis medialis, thus suggesting that this cortical region constitutes the rat's gustatory (insular) cortex. We consider the cortex situated posterior to the gustatory cortex in and above the rhinal sulcus as the core region of the rat's (associative) insular cortex, as this cortex receives afferents from the regions of and between the nuclei suprageniculatus and geniculatus medialis, pars magnocellularis. It includes parts of the cortex termed perirhinal in other studies. The cortex dorsal and posterior to the insular cortex we consider auditory cortex, as it receives afferents from the principal part of the medial geniculate nucleus, and the cortex ventral to the insular cortex (below the fundus of the rhinal sulcus) we consider to constitute the prepiriform cortex, which is athalamic. The posterior part of the perirhinal cortex (area 35) receives afferents from nonspecific thalamic nuclei (midline nuclei). Cortical afferents to the injection loci arise from a number of regions, above all from regions of the medial and sulcal prefrontal cortex. Those injections confined to the projection cortex of the suprageniculate-magnocellular medial geniculate nuclear complex also led to labeling in contralateral prefrontal regions, particularly in area 25 (infralimbic region). A comparison of our results with those on the insular cortex of cats and monkeys suggests that on the basis of thalamocortical connections, topographical relations, and involvements of neurons in information processing and overt behavior, the insular cortex has to be regarded as a heterogeneous region which may be separated into prefrontal insular, gustatory (somatosensory) insular, and associative insular portions.

Transmitter-like action of ATP on patched membranes of cultured myoblasts and myotubes.

Abstract: The concept of purinergic neurotransmission, first proposed by Burnstock1, has been confirmed in various cell types We show here, by the patch-clamp method2, that external ATP in micromotor concentrations (1–100 µM) activates cation channels in the membranes of fusion-competent myoblasts and myotubes In cell-attached membrane patches of myoblasts and myotubes the mean number of simultaneously activated channels increases with time after external ATP application In myoblasts only one population of channels having a mean single-channel conductance of γ=43 pS was found, while in myotubes two populations with γ1=48 pS and γ2 = 20 pS were observed Treatment of myotube membranes with acetylcholine (ACh) or carbachol resulted in two populations of channels which had conductance values and voltage-dependent mean channel lifetimes similar to those produced in response to ATP The results show that embryonic skeletal muscle cells contain cation channels sensitive to ATP and provide evidence for a neurotransmitter-like action of ATP on these cells

Isolation and characterization of a nicotinic acid-degrading sulfate-reducing bacterium, Desulfococcus niacini sp. nov.

Abstract: The strains NAV-1, NAV-2, NAV-3 of new nonsporing sulfate-reducing bacteria with spherical to oval motile cells were isolated with nicotinic acid as electron donor and carbon source. All strains were obtained from marine sediment samples. Growth occurred in defined anaerobic salt water media supplemented with biotin and thiamine as growth factors. Utilization of nicotinic acid depended on the addition of selenite (10-8–10-7 mol/l); requirement for molybdate was not detected. Further compounds utilized as electron donors and carbon sources were hydrogen plus carbon dioxide, formate, acetate, propionate, higher fatty acids up to 16 carbon atoms, alcohols, pyruvate, malate, fumarate, succinate, glutarate, glutamate and pimelate. On hydrogen plus carbon dioxide or on formate, slow growth was obtained without an additional organic carbon source. Growth on acetate or propionate as sole organic substrates was possible, however, it was extremely slow. Stoichiometric measurements revealed that nicotinic acid was completely oxidized to carbon dioxide and ammonia. The average growth yield was 38 g cell dry weight per mol of nicotinic acid used. 3-Phenylpropionate was oxidized to carbon dioxide and benzoate; benzoate could not be oxidized further. The strains were able to reduce sulfite or thiosulfate instead of sulfate. No growth on organic compounds was observed in the absence of an electron acceptor. In the cell membrane fraction, b-type cytochrome was identified; desulfoviridin was not detected. Cell-free extracts oxidized nicotinic acid, nicotinamide or pyrazine-2-carboxylic acid with methylviologen as electron acceptor. Strain NAV-1 is described as type strain of the new species Desulfococcus niacini.

Egyptian blue — Cuprorivaite a window to ancient Egyptian technology

Abstract: Egyptian Blue, a multicomponent synthetic blue pigment has been recorded in ancient Egypt since the Fourth Dynasty of the Old Kingdom (2600–2480 B.C.). The pigment consisting of cuprorivaite (CaCuSi4O10) with variable amounts of wollastonite (CaSiO3), Cu-rich glass and cuprite (Cu3O) or tenorite (CuO) was prepared by melting the copper-rich ingredient with lime and desert sand. Low melting temperatures (below 742 °C) were achieved by addition of flux-like plant ashes. The high quality of the pigments collected from monuments of the Fifth Dynasty (2480–2320 B.C.) may indicate that the first manufacture was in early dynastic or perhaps predynastic eras. During the reign of Thutmosis III (18th Dynasty, 1490–1436 B.C.) probably bronze filings were first applied as starting material, thus indicating a technological innovation. This new method was employed till the Roman times.

Distribution of plastocyanin and soluble plastidic cytochrome c in various classes of algae

Abstract: Several eukaryotic algae belonging to the main taxonomic classes have been cultured autotrophically in liquid medium supplemented with or depleted of copper to assay their ability to form plastocyanin or exchange it against plastidic cytochrome c-553. Most Chlorophyceae are able to substitute cytochrome c-533 for plastocyanin with some exceptions like Haematococcus or Dunaliella, which can only synthesize plastocyanin. Also within the Chlorella group, about half of the 28 strains assayed cannot synthesize cytochrome c-553 under copper deficiency. Species of Chrysophyceae, Xanthophyceae, and Rhodophyceae, on the other hand, cannot synthesize plastocyanin even when a comparatively high copper concentration (10μM) is available.

The Welfare State and the Economy in Periods of Economic Crisis: A Comparative Study of Twenty‐three OECD Nations

Abstract: While all industrial nations have been plagued by the setback to economic growth since the mid-1970s, a wide range of variation marks the economic performance, policy outputs and policy outcomes of Western nations. The basic question addressed in this paper is the extent to which economic, socioeconomic and political variables account for the differences in economic performance, unemployment, public debt and the growth of social security expenditure. In general, the forces which shape public policies in periods of economic crisis tend to be different in character from the major determinants of policy-making in periods of prosperity. The analysis does not support the view that bourgeois and socialist governments produce clear-cut policy differences. It suggests that the major determinants of policies are the power relations in extra-parliamentary arenas, the level of national economic strength prior to the crisis, the extent to which ‘solidaristic’ values characterize the political culture, and the extent to which a correspondence exists between the power relationships in the political ‘superstructure’ and in the party system and industrial arenas. An expanding capitalist order is, in theory, not incompatible with low unemployment and a developed welfare state. However, the governments’ room to manoeuvre is strongly restricted by political and technological developments. One of the major political restrictions is the ‘paradoxical’ outcome of elections.

Fibre type specific transformations in the enzyme activity pattern of rat vastus lateralis muscle by prolonged endurance training.

Abstract: The alterations in activity patterns of representative enzymes in energy metabolism were investigated in the superficial (white) and deep (red) portions of the fast vastus lateralis muscle of the adult rat in response to prolonged endurance training. It was found that following 15 weeks of extreme training (final running duration: 210 min per day, 27 m/min at 15 degree grade), increases in the activities of marker enzymes of the citric acid cycle (citrate synthase), beta-oxidation (3-hydroxyacyl CoA dehydrogenase), and ketone body utilization (3-ketoacid CoA transferase) as well as of glutamate pyruvate transaminase occurred in both regions of the muscle, with the greatest increase being observed in the superficial portion (2.6-4.2-fold). Pronounced increases were also seen for hexokinase which showed highest activities after 7 weeks of training. Conversely, decreases were noted for various glycogenolytic, glycolytic and gluconeogenic enzymes (phosphorylase, glyceraldehydephosphate dehydrogenase, pyruvate kinase, lactate dehydrogenase and fructose-1,6-diphosphatase). Reduction in the activities of these enzymes was most pronounced in the deep portion of the muscle. These results demonstrate a fundamental rearrangement of the energy metabolism of the muscle in response to prolonged, high intensity training. In the case of the deep portion of the vastus lateralis muscle, which has been shown to be composed of a large percentage of fast oxidative-glycolytic fibres (FOG), the enzyme profile becomes similar to the slow oxidative (SO) fibre. In the superficial portion which contains predominantly fast glycolytic fibres (FG), the enzyme profile becomes similar to FOG fibres.(ABSTRACT TRUNCATED AT 250 WORDS)

Demonstration that milk cells invade the suckling neonatal mouse.

Abstract: Mouse milk cells were stained with rhodamine or fluorescein isothiocyanate and fed to young suckling mice By visual examination of serial sections and by flow cytofluorometry, we were able to demonstrate directly the presence of these cells in peripheral tissues It was estimated that at least 01% of the fed cells might infiltrate the young mouse, which is initially immunologically defenseless This is in accordance with evidence from many sources for activity of maternally-derived lymphoid cells in young rodents

Ipsi- and contralateral fibre transformations by cross-reinnervation. A principle of symmetry.

Abstract: Cross-reinnervation of rabbit soleus muscle by the peroneal nerve induces a 90% transformation of slow into fast fibres. These changes are reflected in corresponding transformations of the enzyme activity pattern of energy metabolism, the isozyme pattern of lactate dehydrogenase and, in confirmation of previous results (Srihari et al. 1981), transitions from a slow to a fast type myosin light chain pattern. The transformation process appears to be complete after 6 months. Similar changes, although less extensive are also found in the soleus muscle of the contralateral leg. Fibre type transitions in the contralateral muscle are not accompanied by fibre type grouping, as seen in the cross-reinnervated muscle and therefore these changes appear to result from a transformation of the motor units themselves. This phenomenon is interpreted as a compensatory process in maintaining symmetry within the neuromotor system.

The specificity of central nervous projections of locust mechanoreceptors.

Abstract: The central projections of hairplates and groups of campaniform sensilla of various parts of the locust head, neck, and thorax are compared. Receptors with approximately the same peripheral location (e.g., dorsal head, wing, or proximal leg) tend to exhibit similar central projection patterns. Specificity of the projections due to different morphological types of sensory neurones may influence shape and extent of segmental ramifications; this is observed with receptors of the proximal leg joints in particular.

Serotonin-like immunoreactivity in the optic lobes of three insect species.

Abstract: The cellular localization of 5-HT in the optic lobes of three insect species was assayed with the use of antibodies raised against 5-HT. In Schistocerca, Periplaneta, and Calliphora all neuropil regions of the optic lobe, the lamina, medulla and lobula, contain 5-HT-immunoreactive varicose fibres in different patterns, like columns and layers. Such fibres also connect the lobula to neuropil in the lateral protocerebrum. In Calliphora also 5-HT-positive fibres of the medulla and lobula plate have projections to the lateral protocerebrum, whereas the origin of the lamina fibres is not certain. In all species the processes displaying 5-HT-like immunoreactivity appear to be derived from a relatively small number of cell bodies, each neuron thus having processes over a large volume of the neuropil of the optic lobe in different layers.

Two telestimulation systems for chronic indirect muscle stimulation in caged rabbits and mice

Abstract: Telestimulation systems are described for chronic indirect muscle stimulation in caged rabbits and mice. Both system use a 5 MHz carrier frequency transmission and consist of a transmitter and a receiver. The latter is fixed to the back of the animal.

Identified muscle fibers in a crab. I: Characteristics of excitatory and inhibitory neuromuscular transmission

Abstract: 1. A set of 10 superficial fibers is described for the closer muscle of the crabEriphia spinifrons. The fibers are found in identical positions from one preparation to the next. 2. According to innervation pattern and neuromuscular responses, the identified fibers can be classified in 4 major groups (I to IV). They are representative for the remaining fibers comprising the closer muscle. 3. All muscle fibers of the closer are innervated by the fast excitor. Only the fibers also innervated by the slow excitor are further innervated by the common inhibitor (CI). CI innervation seems to be linked to the distribution of the slow axon. 4. CI is most effective in fibers 2, 3 and 4 (group I fibers) through post- and mainly presynaptic mechanisms. Presynaptic inhibition drastically reduces excitatory transmission at the terminals of both the slow and the fast axon. Fiber 5 (group II fibers) receive(s) only postsynaptic inhibition. 5. The strength of presynaptic inhibition varies at different junctions along a given muscle fiber from about 20 to almost 100%. 6. Excitatory and inhibitory nerve terminal potentials were recorded allowing determination of the time relationship for optimal presynaptic inhibition. Inhibition reaches its optimum when the action potential in the inhibitory ending precedes that in the excitatory terminal by 5 to 8 ms. Presynaptic inhibition shows a long persistance. Half maximal inhibition is present when action potentials in the inhibitory endings occur 18 to 30 ms before those in the excitatory endings. 7. CI plays an important role in the division of labor among muscle fibers receiving identical excitatory input. Fibers of group I (tonic fibers) are selectively inhibited and prevented from participation in tension generation during walking of the crab. During locomotion mainly group II fibers are active. A very large proportion of muscle fibers (group III and IV) appears not to be activated during slow walking.

Long-Term Changes in Chemostat Cultures of Cytophaga johnsonae

Abstract: Long-term studies with a gliding, heterotrophic bacterium, Cytophaga johnsonae, were conducted in a glucose-limited chemostat at a high and a low dilution rate. To test the stability of the steady state during long-term experiments the following parameters were monitored: optical density, glucose concentration, glucose uptake potential, ATP content of the cells, and plate counts on two different agar media. Biomass remained relatively constant, although the observed changes could have been possible in both directions. During all steady states, glucose uptake showed a stepwise increase and the glucose concentration showed a corresponding decrease. Glucose uptake potential and glucose concentration in the chemostat were inversely proportional. The ATP content of the cells varied up to 33% during the steady state, but did not show a general trend. After long cultivation in all chemostats, plate counts on both agars dropped to values less than 20% of the original steady-state level. These decreases were due to an inability of the cells to grow on agar plates, not to a lack of vitality of the cells in the chemostat. This study showed that even during shorter chemostat runs, e.g., 1 week, changes in important parameters with the steady state must be expected, especially in the uptake potential and the concentration of the limiting substrate.

Intracellular Na+ and Ca2+ in leech Retzius neurones during inhibition of the Na+−K+ pump

Abstract: The intracellular Na activity,aNai, and the intracellular Ca activity,aCai, were measured with double-barrelled neutral carrier Na+- and Ca2+-sensitive microelectrodes in Retzius neurones in the central nervous system of the leechHirudo medicinalis. TheaNai was measured to be 8.0 mM (corrected for Ca interference), which corresponds to a cytoplasmic Na+ concentration of 10.7 mM, assuming a Na activity coefficient of 0.75. The calculated Na+ equilibrium potential was 59 mV, giving a total Na+ electrochemical gradient of approximately 102 mV. TheaCai was found to range between 1 and 5×10−7 M, from which a Ca2+ equilibrium potential near +120 mV was estimated. When the Na+−K+ pump was inhibited by lowering the external K+ concentration or by adding the glycoside ouabain (5×10−4 M), theaNai reversibly increased severalfold. WhenaNai increased to high levels following complete pump inhibition, theaCai increased above 10−6 M, and the membrane input resistance decreased. After removal of ouabain,aNai,aCai and the membrane resistance recovered within 30 min after a delay of 20–40 min. Our results suggest that a large increase ofaNai produces a rise inaCai, possibly by means of a Na+−Ca2+ exchange across the cell membrane. The elevation of theaCai may be responsible for the decrease in membrane resistance, and may also be related to the uncoupling of the paired Retzius neurones observed in the presence of Na+−K+ pump inhibitors.

Growth of bacteria in inorganic medium at different levels of airborne organic substances.

Abstract: Invasion rates of airborne organic substances into sterile mineral medium were compared by using flasks closed with cotton stoppers, silicone stoppers, and screw caps with Teflon gaskets. The resulting increases of dissolved organic carbon were 0.5, 0.2, and 0 mg/liter per week, respectively. The compounds supported the growth of lake water bacteria and a strain of Pseudomonas fluorescens. Growth rates were correlated to the permeability of the stoppers used. The measured input of organic carbon in the sterile mineral medium is considered to be a minimum value for the actual contribution of organic compounds by the air. Multiplication rates of the bacteria suggest that the organisms prevent the escape of volatile organic substances from the medium by rapid utilization. The steady nutrient supply through the air should be considered in growth experiments with bacteria at low concentrations of nutrients.