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11.
12.
Methanobacterium thermoaggregans is a new thermophilic autotrophic rod-shaped methane producing bacterium. The organism likes to form aggregates during growth and utilizes only H2 and CO2 as substrates. Growth optimum is at 65°C with a doubling time of 3.5 h. Optimal growth occurs at pH-values between 7 and 7.5. The addition of yeast extract to the mineral salt medium stimulates growth. The DNA base composition is 42 mol% G+C. The organism was isolated from mud taken from a cattle pasture. Because of its optimal growth temperature and its tendency to form aggregates the nameMethanobacterium thermoaggregans is suggested.Abbreviations G+C
Guanine+cytosine 相似文献
13.
Achim Recktenwald Karl-Heinz Kroner Maria-Regina Kula 《Enzyme and microbial technology》1985,7(12):607-612
Flow injection analysis (FIA) has been employed to automate enzyme assays for formate dehydrogenase (FDH) and l-leucine dehydrogenase (l-LeuDH). Coupled to a special sampling device the FIA assays were used to monitor on-line downstream processes, e.g. disintegration of microbial cells and cross-flow filtration of cell homogenates. 相似文献
14.
Karl-Heinz Schmidt 《Journal of Ornithology》1984,125(3):321-331
Zusammenfassung Die jährlichen Schwankungen im Legebeginn bei Kohl-, Blau-, Sumpf- und Tannenmeisen sind mit den Frühjahrstemperaturen (Wärmesummen) korreliert. Für KM, BM und SM sind die Wärmesummen in einem 4-Wochen-Zeitraum — Mitte März bis Mitte April — ausschlaggebend. Für TM sind lediglich die Wärmesummen von 2 Wochen — Anfang bis Mitte April — entscheidend. Die Wirksamkeit von Temperaturen in 4- bzw. 2-Wochen-Zeiträumen vermag auch zu erklären, warum KM, BM und SM alljährlich ähnliche Zeitverschiebungen im Legetermin zeigen, TM hingegen die geringste Übereinstimmung mit den anderen Meisenarten besitzen. KM, BM und SM reagieren erst, wenn Frühjahrstemperaturen die 6°C- oder 8°C-Schwelle überschreiten. TM scheinen auch auf niedrigere Temperaturen anzusprechen. Der Laubaustrieb von Buchen, Fichten und Stieleichen wird durch Frühjahrstemperaturen (Wärmesummen) stark beeinflußt. Fichten und Eichen reagieren besonders stark auf Temperaturen von Anfang bis Mitte April, Rotbuchen am stärksten von Mitte März bis Mitte April. Die höchsten Korrelationen ergaben sich bei der 6°C- und 8°C-Schwelle. Zwischen Legebeginn und Laubausbruch von Buchen und Fichten besteht ein statistisch gesicherter Zusammenhang. Der Laubaustrieb von Eichen ist bei 3 von 4 Meisenarten nicht mit der Eiablage korreliert. Eine Steuerung der Eiablage durch den Anblick frisch ausgetriebener Blätter ist auszuschließen. Der Eiablagebeginn der Meisen scheint am besten mit dem Laubaustrieb der jeweils häufigsten Baumart in einer bestimmten Region synchronisiert zu sein.
Spring temperature and time of laying in tits
Summary The yearly variations in the start of laying by Great Tits(Parus major), Blue Tits(P. caeruleus), Marsh Tits(P. palustris) and Coal Tits(P. ater) are correlated with the spring temperatures (heat sums). The heat sums over a period of 4 weeks from mid March to mid April are of crucial importance for Great Tits, Blue Tits and Marsh Tits, whereas for Coal Tits only the heat sums of the 2 weeks from the beginning to the middle of April are decisive. The influence of temperature during 4 or 2 week periods, also explains why Great Tits, Blue Tits and Marsh Tits show similar variation in laying dates every year, whereas Coal Tits show the lowest correlation with other species of tits. Great Tits, Blue Tits and Marsh Tits only react to spring temperatures exceeding 6°C or 8°C. Coal Tits also seem to be susceptible to low temperatures. Beech(Fagus sylvatica), pine(Picea abies) and oak(Quercus robur) leafing is greatly influenced by spring temperatures (heat sums). Pine and oak react especially strongly to temperatures from the beginning to the middle of April. Temperature influence on beech leafing is most pronounced from mid March to mid April. The highest correlations occurred at the 6°C and 8°C threshold. There is firm statistical evidence of a connection between the 4 tit species' timing of laying and beech and pine leafing. Oak leafing is not correlated with the egg laying of 3 of the 4 tit species. The possibility that the sight of freshly opened leaves triggers egg laying must be ruled out, as tits start laying, with a few exceptions, before leafing starts. The start of laying seems for the tits to be best synchronized with the leafing of the most prevalent type of tree in a particular region.相似文献
15.
Summary Voltage-clamped single nerve fibers of the frogRana esculenta were treated with the carboxyl group activating reagent N-ethoxy-carbonyl-2-ethoxy-1,2-dihydroquinoline (EEDQ) in the presence of different primary amines and without added amine. Carboxyl groups form stable amide bonds with primary amines in the presence of EEDQ. EEDQ treatment reduced the sodium current considerably and irreversibly, regardless of the presence of a primary amine in the Ringer's solution. The potassium current was also reduced. After modification the reduced sodium currents inactivated slowly and incompletely. The descending branch of the sodium current-voltage relation,I
Na(E), was shifted along the voltage axis in the depolarizing direction. The size of the shift was strongly dependent on the amine present during modification with EEDQ. The voltage-dependence of sodium inactivation,h
x
(E), was shifted to more positive values of membrane potential by EEDQ in the presence of ethylenediamine (11 mV) and glucosamine (3 mV). In contrast, a small shift to more negative potentials occurred in the presence of taurine (–3 mV) or without the addition of an amine (–2 mV). A tenfold increase of the calcium concentration still shifted theI
Na(E) andh
x
(E) curves of the chemically modified fibers. However, these shifts were smaller than those observed on untreated fibers. The currents remaining after the modification were completely blocked by tetrodotoxin; no change of the reversal potential occurred. 相似文献
16.
Single-channel conductance fluctuations are analysed for gramicidin A incorporated into binary-mixed black lipid membranes of charged phosphatidic acid and neutral lecithin in different molar ratios. At very low Ca++ concentrations in the electrolyte (i.e. in the presence of EDTA) homogeneous lipid mixtures are identified through their conductance and life time probability distributions for integral gramicidin pores. As for the pure lipid components, the conductance histograms each show a single maximum with regular width and for all channels a single mean lifetime is found.For Ca++-levels (10-6–10-5
M) that are close to the critical demixing concentration (10-4
M) unusually broad conductance distributions and reduced lifetimes are found provided the PC content, x, of the membrane is close to the critical mixture (x
crit0.5). We interpret this as a first example of the coupling of a membrane function (the transport of ions) to a lipid matrix with locally fluctuating composition close to a critical demixing point.For
the conductance histogram of gramicidin A in an equimolar mixture of PA and PC shows two well-separated maxima. A correlation analysis between conductance and lifetime of the single pores shows that the two channel populations also differ significantly in their mean channel lifetime, *. This finding is interpreted as being direct evidence for Ca++-induced lateral phase separation in black lipid membranes, as has been postulated recently.Abbreviations used HEPES
N-2-hydroxyethyl-piperazine-N-2-ethane-sulfonic acid
- EDTA
ethylenediaminetetraacetic acid 相似文献
17.
Prof. Dr. med. Wolfgang Schulze Martin Riemer Uwe Rehder Karl-Heinz Höhne 《Cell and tissue research》1986,244(1):1-8
Summary With the use of a digital image-processing method three-dimensional reconstructions of the arrangement of spermatocytes in human seminiferous tubules were performed. With this method it was possible to investigate the cellular distribution in the tubule in nearly any given perspective and projection. In addition, by means of simple mathematical procedures, such as by transformation of Cartesian coordinates into cylindrical coordinates, it was possible to vary the shape of a reconstruction, i.e., to convert the cylindrical image of a tubular portion into a right-angled r--z-representation.The present work not only confirms the existence of a complex helical plan of organization of the human seminiferous epithelium but also provides further aspects of the phenomenon of physiological germ-cell loss and its integration into the kinetics of spermatogenesis.Dedicated to Prof. E.C. Roosen-Runge, Seattle, on the occasion of his 75th birthday 相似文献
18.
Changes in freeze-fractured mitochondrial membranes correlated to their energetic state. Dynamic interactions of the boundary membranes 总被引:6,自引:0,他引:6
Structural changes of mitochondria in correlation to their energetic state have been observed as matrix expansion and condensation. In this communication we describe a morphological correlation in freeze-fractured mitochondrial membranes which is also dependent on the metabolic state of the organelle: the frequency by which the fracture plane following the inner or outer boundary membrane deviates by jumping from one membrane to the other is higher in phosphorylating mitochondria when compared to freshly isolated or energized mitochondria. These deflections of the fracture plane occur mostly in minimal, short steps showing close apposition of the two boundary membranes. We therefore conclude that the observed change in morphological appearance is produced by a change in interactions between the inner and outer membranes correlated to the different functional states of the inner membrane. 相似文献
19.
Eric R. Dabbs Renate Hasenbank Berthold Kastner Karl-Heinz Rak Barbara Wartusch Georg Stöffler 《Molecular & general genetics : MGG》1983,192(3):301-308
Summary A battery of immunological tests were used to investigate mutants which had been determined as lacking one or two ribosomal proteins on the basis of two-dimensional polyacrylamide gels. Proteins which were confirmed as missing from the ribosome in one or more mutants were large subunit proteins L1, L15, L19, L24, L27, L28, L30 and L33 and small subunit proteins S1, S9, S17 and S20. Cross-reacting material (CRM) was also absent from the post-ribosomal supernatant except in the case of protein S1. Since mutants lacking protein L11 have been previously described, any one of 13 of the 52 ribosomal proteins can be missing. None of these 13 proteins, except S1, can therefore have an indispensable role in ribosome function or assembly. In several mutants in which a protein was not missing but altered, it was present as several moieties of differing charge and size. 相似文献
20.
Jürgen Ebel Brbel Schaller-Hekeler Karl-Heinz Kobloch Eckard Wellman Hans Grisebach Klaus Hahlbrock 《Biochimica et Biophysica Acta (BBA)/General Subjects》1974,362(3):417-424
Variations in teh activities of several enzymes of phenylpropanoid metabolism were studied in fermenter-grown cell suspension cultures of soyben (Glycine max).Concomitant large increases and subsequent decreases in the activities of phenylalanine ammonina-lyase (EC 4.3.1.5), cinnamic acid 4-hydroxylase, and two isoenzymes of p-coumarate:CoA ligase occurred prior to the stationary phase of the cell cultures. These findings represent a further example of an interdependent regulation of these enzymes of the general phenylpropanoid metabolism.The increases in all of these enzyme activities could be further enhanced by illunination of the cells.No comparable light effects and no significant changes were observed for the specific activity of an S-adenosylmethionine:o-dihydric phenol m-O-mehyltransferase and for the overall rate of the two-step reduction of feruloyl-CoA to coniferyl alcohol. These enzymatic reactions therefore appear to be regulated independently of the enzymes of the general phenylpropanoid metabolism. 相似文献