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1.
D. Haferburg R. Hommel H.-P. Kleber S. Kluge G. Schuster H.-J. Zschiegner 《Engineering in Life Science》1987,7(4):353-356
A rhamnolipid released by Pseudomonas aeruginosa 196 Aa into the culture medium reduced the number of local lesions induced by tobacco mosaic virus on leaves of the hypersensitive host Nicotiana glutinosa L. by up to 90%. The content of potato virus X in the systemically infected host Nicotiana tabacum L. ‘Samsun’ is decreased in inoculated as well as in secondarily infected leaves by up to 50%. In a smaller degree red clover mottle virus is influenced in the systemic host Pisum sativumconvar.speciosum (Dierb.) Alef ‘Nadja’. 相似文献
2.
The effects of an extracellular microbial glycolipid, the interfacial active lactonic sophoroselipid, and of Triton X-100 on strains of Acinetobacter calcoaceticus are compared. Sophoroselipid diminished growth rates on n-heptadecane. Both surfactants led to the excretion of enzyme activities into the culture medium. Sophoroselipid increased the release of cytoplasmic malate dehydrogenase whereas in presence of Triton X-100 the quinoprotein glucose dehydrogenase was also excreted in large amounts. 相似文献
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A method for the separation of the outer membrane (OM) from the cytoplasmic membrane (CM) of Acinetobacter calcoaceticus 69/V grown on different carbon sources is described. The contamination of the OM with CM was less than 10%. Independent of the carbon source, five protein bands with apparent molecular weights of 47 000, 33000, 21 000, 19 000 and 12 000 were found by solubilization at 37°C and six bands at 100°C (apparent Mr 53 000, 47 000, 38 000, 26 000, 21000, 12000). Three proteins were modifiable by heat. With the periodic acid-Schiff procedure the bands with apparent Mr of 33 000 and 12 000 were made visible. After growth on d,l-carnitine an additional two non-heat-modifiable protein bands with apparent Mr between 40 000 and 45 000 were detected. By cultivation on acetate and peptone as carbon source one additional band (Mr 15 000) from OM of cells could be found. 相似文献
6.
Hans-Peter Kleber Hermann Seim Harald Aurich Erich Strack 《Archives of microbiology》1977,112(2):201-206
Zusammenfassung Die Verwertung von Carnitin und Carnitinderivaten (O-Acylcarnitine, Carnitincarboxyl-derivate) und strukturverwandten Trimethylammoniumverbindungen (Betaine und Stickstoffbasen) durch Acinetobacter calcoaceticus wurde anhand des Wachstums und des quantitativen Nachweises der Metabolite untersucht. Der Stamm wuchs auf l-Carnitin, l-O-Acylcarnitinen und -Butyrobetain als jeweils einziger C-Quelle. Der Verbrauch dieser Verbindungen und das Wachstum korrelierten mit der Spaltung der C-N-Bindung und mit dem gebildeten Trimethylamin. d-Carnitin wurde metabolisiert, wenn als zusätzliche C-Quelle l-Carnitin im Nährmedium vorhanden war, oder wenn die Bakterien mit l-oder dl-Carnitin vorinkubiert worden waren. Mit d-Carnitin als einziger C-Quelle wuchsen die Bakterien jedoch nicht. Die Bakterien oxidierten Cholin zu Glycinbetain in Gegenwart einer zusätzlichen C-Quelle, Glycinbetain selbst wurde nicht assimiliert. In Hinsicht auf den Abbau quaternärer Stickstoffverbindungen besitzt Acinetobacter calcoaceticus im Vergleich zu anderen Carnitin-verwertenden Bakterienarten einen für ihn charakteristischen Stoffwechselweg.
Utilization of trimethylammonium-compounds by Acinetobacter calcoaceticus
The utilization of carnitine and carnitine derivatives (O-acylcarnitines, carnitine carboxylderivatives) and structure-related trimethylammonium-compounds (betaines and nitrogen-bases) by Acinetobacter calcoaceticus was studied by means of the control of growth and the quantitative detection of metabolites. The strain grew only on l-carnitine, l-O-acylcarnitines, and -butyrobetaine as the sole carbon sources. The utilization of these compounds and the growth correlated with the cleavage of the C-N bond and thereby with the formation of trimethylamine. d-Carnitine was metabolized, if an additional carbon source, like l-carnitine, was present in the incubation mixture, or if the bacteria were preincubated with l-or dl-carnitine, but no growth was observed on d-carnitine as the sole carbon source. The bacteria oxidized choline to glycinebetaine in the presence of additional carbon sources, glycinebetaine itself was not assimilated. With regard to the catabolism of quaternary nitrogen compounds Acinetobacter calcoaceticus shows a different pathway in comparison with other bacterial species metabolizing carnitine.相似文献
7.
Hermann Seim Heinz Löster Reiner Claus Hans-Peter Kleber Erich Strack 《Archives of microbiology》1982,132(1):91-95
In view of the development of al-carnitine deficiency, the metabolism ofl-carnitine and structure-related trimethylammonium compounds was studied inSalmonella typhimurium LT2 by means of thin-layer chromatography (TLC).l-Carnitine, crotonobetaine and acetyl-l-carnitine stimulated the anaerobic growth in a complex medium significantly. The stimulation depended on the formation of -butyrobetaine. The reduction ofl-carnitine proceeded in two steps: (1) Dehydration of thel-carnitine to crotonobetaine, (2) hydrogenation of crotonobetaine to -butyrobetaine. The reduction of crotonobetaine was responsible for the growth stimulation. Terminal electron acceptors of the anaerobic respiration such as nitrate and trimethylamine N-oxide, but not fumarate, suppressed the catabolism ofl-carnitine completely. Glucose fermentation, too, inhibited the reduction ofl-carnitine but optimal growth with a high carnitine catabolism was achieved byd-ribose. The esters of carnitine with medium- and long-chain fatty acids inhibited the growth considerably because of their detergent properties.Abbreviations TLC
thin-layer chromatography 相似文献
8.
beta-Endorphin- and ACTH-like immunoreactive peptides were measured in plasma and certain tissues of a patient suffering from an oat-cell-carcinoma of the lungs and Cushing's syndrome. Using sensitive radioimmunoassays in combination with gel-filtration, highly elevated levels of beta-endorphin, beta-lipotropin (beta-LPH), alpha-melanotropin (alpha-MSH) and ACTH were found. 相似文献
9.
Denis J. Miller Herbert Kleber Joseph R. Bloomer 《The Yale journal of biology and medicine》1979,52(1):135-140
One hundred and seventy-seven former heroin addicts, consisting of 85 who were newly admitted to a methadone maintenance program and 92 who had received methadone for a mean period of 30 months, were prospectively studied for up to 2 years in order to determine: (1) the effect of heroin withdrawal on the hepatic abnormalities, and (2) the incidence of HBsAg, anti-HBs, and anti-HCc as indices of the frequency of hepatitis B virus infection. Our study indicates that (1) hepatic abnormalities persist when heroin is discontinued and are not temporally related to drug and/or needle usage, and (2) that 71% of subjects had either HBsAg or anti-HBs; anti-HBc was tested for in 16 patients and was present in 100%, although 9 of the 16 were both HBsAg- and anti-HBs-negative. This study suggests that hepatitis B is largely responsible for the liver dysfunction. It is proposed that an abnormality in immune function, induced by heroin, is responsible for the high incidence of chronic hepatitis. Attention is drawn to the similarity between former drug addicts and hemophiliacs, since both develop chronic hepatitis in spite of anti-HBs in the serum. 相似文献
10.
In this paper, we propose a structure for organo-mineral associations in soils based on recent insights concerning the molecular
structure of soil organic matter (SOM), and on extensive published evidence from empirical studies of organo-mineral interfaces.
Our conceptual model assumes that SOM consists of a heterogeneous mixture of compounds that display a range of amphiphilic
or surfactant-like properties, and are capable of self-organization in aqueous solution. An extension of this self-organizational
behavior in solution, we suggest that SOM sorbs to mineral surfaces in a discrete zonal sequence. In the contact zone, the formation of particularly strong organo-mineral associations appears to be favored by situations where either (i) polar
organic functional groups of amphiphiles interact via ligand exchange with singly coordinated mineral hydroxyls, forming stable
inner-sphere complexes, or (ii) proteinaceous materials unfold upon adsorption, thus increasing adhesive strength by adding
hydrophobic interactions to electrostatic binding. Entropic considerations dictate that exposed hydrophobic portions of amphiphilic
molecules adsorbed directly to mineral surfaces be shielded from the polar aqueous phase through association with hydrophobic
moieties of other amphiphilic molecules. This process can create a membrane-like bilayer containing a hydrophobic zone, whose components may exchange more easily with the surrounding soil solution than those in the contact zone, but which are
still retained with considerable force. Sorbed to the hydrophilic exterior of hemimicellar coatings, or to adsorbed proteins,
are organic molecules forming an outer region, or kinetic zone, that is loosely retained by cation bridging, hydrogen bonding, and other interactions. Organic material in the kinetic zone
may experience high exchange rates with the surrounding soil solution, leading to short residence times for individual molecular
fragments. The thickness of this outer region would depend more on input than on the availability of binding sites, and would
largely be controlled by exchange kinetics. Movement of organics into and out of this outer region can thus be viewed as similar
to a phase-partitioning process. The zonal concept of organo-mineral interactions presented here offers a new basis for understanding
and predicting the retention of organic compounds, including contaminants, in soils and sediments. 相似文献