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991.
Armin Merckelbach Stefanie Gödecke Zbigniew A. Janowicz Cornelis P. Hollenberg 《Applied microbiology and biotechnology》1993,40(2-3):361-364
The ura3 gene of Hansenula polymorpha was cloned, sequenced and used to generate a ura3 mutant from the wild-type strain of this yeast via integrative mutagenesis. The Tn5 neomycin-resistance marker (neo) under control of the ADH1 promoter from Saccharomyces cerevisiae served as a transformation marker. The results show that gene replacement can be achieved in H. polymorpha, a yeast with a high level of non-homologous integration.
Correspondence to: C. P. Hollenberg 相似文献
992.
Utility of DNA amplified by degenerate oligonucleotide-primed PCR (DOP-PCR) from the total genome and defined chromosomal regions of field bean 总被引:7,自引:0,他引:7
Uta Pich Andreas Houben J?rg Fuchs Armin Meister Ingo Schubert 《Molecular & general genetics : MGG》1994,243(2):173-177
Degenerate oligonucleotide primed (DOP)-PCR has emerged as a simple and rapid method for representative amplification of highly complex genomic DNA from humans, mice and Drosophila. The present paper describes the adaptation of this method for use on a plant species, Vicia faba, with a large genome (2C = 30 pg). Specific low-copy-number sequences as well as highly repeated sequences were detectable among DOP-PCR products obtained from small samples of purified genomic DNA (100 pg), DNA from 10 prophase nuclei, 10 flow-sorted chromosomes or 15 microdissected chromosome segments (satellites) following reamplification with sequence-specific primers and/or Southern hybridization. Biotinylated chromosome-specific DOP-PCR products were used for fluorescent in situ hybridization. All chromosomes showed hybridization signals, with the exception of regions containing Fok elements which are not present in the chromosomal DNA targeted by DOP-PCR. 相似文献
993.
Enantioselective GC analysis of 4-ethyloctanoic and 4-methylheptanoic acid, using heptakis(2,3-di-O-methyl-6-O-tert-butyldimethylsilyl)-β-cyclodextrin as the chiral stationary phase, is described and the sensory properties of several 4-alkyl-branched acids, using gas chromatography-olfactometry (GC-O) equipment and octakis(2,3-di-O-methyl-6-tert-butyldimethylsilyl)-γ-cyclodextrin as the stationary phase, are evaluated. The chirospecific analysis of various 2-, 3-, and 4-alkyl-branched acids from commercially available Roman chamomile (Chamaemelum nobile (L.) Allioni), Parmesan cheese, and subcutaneous mutton adipose tissue, using either GC-GC (MDGC) or GC-MS analytical methods, is described. © 1994 Wiley-Liss, Inc. 相似文献
994.
995.
Markus Otto Jens Wiltfang Ekkehard Schütz Inga Zerr Anke Otto Annette Pfahlberg Olaf Gefeller Manfred Uhr Armin Giese Thomas Weber Hans A Kretzschmar Sigrid Poser 《BMJ (Clinical research ed.)》1998,316(7131):577-582
Objective: To analyse serum concentrations of brain specific S100 protein in patients with Creutzfeldt-Jakob disease and in controls. Design: Prospective case-control study. Setting: National Creutzfeldt-Jakob disease surveillance unit. Subjects: 224 patients referred to the surveillance unit with suspected Creutzfeldt-Jakob disease and 35 control patients without dementia. Main outcome measure: Serum concentration of S100 protein in patients with Creutzfeldt-Jakob disease, in patients with other diseases causing dementia, and in the control group. Results: Of the 224 patients with suspected Creutzfeldt-Jakob disease, 65 were classed as definitely having the disease after neuropathological verification, an additional 6 were classed as definitely having the disease as a result of a genetic mutation, 43 as probably having the disease, 36 as possibly having the disease, and 74 patients were classed as having other disease. In the 108 patients classed as definitely or probably having Creutzfeldt-Jakob disease the median serum concentration of S100 was 395 pg/ml (SD 387 pg/ml). This was significantly higher than concentrations found in the 74 patients classed as having other diseases (median 109 pg/ml; SD 177 pg/ml; P=0.0001). At a cut off point of 213 pg/ml sensitivity for the diagnosis of the disease was 77.8% (95% confidence interval 68.8% to 85.2%) and specificity was 81.1% (70.3% to 89.3%). There was a significant difference in survival at different concentrations of S100 in Kaplan-Meier curves (P=0.023). Conclusion: Measurement of serum concentrations of S100 is a valuable tool which can be used more easily than tests on cerebrospinal fluid in the differential diagnosis of Creutzfeldt-Jakob disease. More studies are needed to determine whether serial testing of serum S100 improves diagnostic accuracy.
Key messages
- Creutzfeldt-Jakob disease is a rare, fatal neurodegenerative disease. Diagnosis is made clinically and neuropathologically
- There is no serum test which allows the diagnosis to be made while the patient is alive
- In this study raised serum concentrations of S100 protein were found in patients with Creutzfeldt-Jakob disease
- Serum concentrations of S100 could be used with a sensitivity of 77.8% and a specificity of 81.1% to confirm Creutzfeldt-Jakob disease in the differential diagnosis of diseases that cause dementia
- Serial measurement of S100 concentrations will enhance diagnostic accuracy
996.
M. Schütz Christof Klughammer Christoph Griesbeck Armin Quentmeier Cornelius G. Friedrich Günter Hauska 《Archives of microbiology》1998,170(5):353-360
Reduction of exogenous ubiquinone and of cytochromes by sulfide in membranes of the chemotrophic bacterium Paracoccus denitrificans GB17 was studied. For sulfide-ubiquinone reductase activity, K
m values of 26 ± 4 and 3.1 ± 0.6 μM were determined from titrations with sulfide and decyl-ubiquinone, respectively. A maximal
rate of up to 0.3 μmol decyl-ubiquinone reduced (mg protein)–1 min–1 was estimated. The reaction was sensitive to quinone-analogous inhibitors, but insensitive to cyanide. Reduction of cytochromes
by sulfide was monitored with an LED-array spectrophotometer. Under oxic conditions, reduction rates and extents of reduction
were lower than those under anoxic conditions. Reoxidation of cytochromes was oxygen-dependent and cyanide-sensitive. The
multiphasic behavior of transient reduction of cytochrome b with limiting amounts of sulfide reflects that sulfide, in addition to acting as an electron donor, is a slowly binding inhibitor
of cytochrome c oxidase. The initial peak of cytochrome b reduction is dependent on electron flow to an oxidant, either oxygen or ferricyanide, and is stimulated by antimycin A. This
oxidant-induced reduction of cytochrome b suggests that electron transport from sulfide in P. denitrificans GB17 employs the cytochrome bc
1 complex via the quinone pool.
Received: 8 April 1998 / Accepted: 29 July 1998 相似文献
997.
Biosurfactants from Bacillus licheniformis: structural analysis and characterization 总被引:6,自引:0,他引:6
Katharina Jenny Othmar Käppeli Armin Fiechter 《Applied microbiology and biotechnology》1991,36(1):5-13
Summary The surface-active compounds of the strain Bacillus licheniformis were isolated and their structure was elucidated. The high surface-active capacity of the crude extract was basically due to traces of long-chain saturated fatty acids, especially of palmitic and stearic acids, to a mixture of small amounts of hydrocarbons with chain lengths of 20 and 22 carbons, and mainly to appreciable amounts of four slightly different lipopeptides. The lipopeptides were found to be a mixture of four closely related compounds. The lipophilic part consisting of i-, n-C14 or i-, ai-C15 -OH fatty acids was linked to the hydrophilic peptide moiety, which contained seven amino acids (Glu, Asp, Val, three Leu and Ile) by a lactone linkage. Fifteen milligrams per litre of the purified lipopeptide product decreased the surface tension of water from 72 mN m–1 to 27 mN m–1, characterizing the product as a powerful surface-active agent that compares favourably to other (bio)surfactants. Antibiotic activity was demonstrated against bacteria and yeasts.
Offsprint requests to: O. Käppeli 相似文献
998.
Mary E. Endress Manfred Hesse Siwert Nilsson Armin Guggisberg Ji-ping Zhu 《Plant Systematics and Evolution》1990,171(1-4):157-185
The genusHolarrhena, described byRobert Brown in 1811, has had a problematic taxonomic history, in part due to a suite of characters that does not conform with accepted concepts within theApocynaceae. In a number of important taxonomic charactersHolarrhena is typical of subfam.Apocynoideae. But due to the relatively unspecialized structure of the anthers most recent authors have placedHolarrheng, together withCarruthersia andSpirolobium, as the subtribeHolarrheninae in subfam.Plumerioideae.
For the present investigation the floral structure and pollen morphology ofHolarrhena, Carruthersia andSpirolobium were analyzed. From the chemical literature reports of the occurrence of steroidal alkaloids in thePlumerioideae were evaluated. Our results indicate that the three genera belong to subfam.Apocynoideae in the tribeNerieae, but that the Holarrheninae is an unnatural group, and that the three genera should be accommodated individually within the tribe. 相似文献
999.
Armin Mosandl Christiane Askari Uwe Hener Dieter Juchelka Detmar Lehmann Peter Kreis Christine Motz Ursula Palm Hans-Georg Schmarr 《Chirality》1992,4(1):50-55
The simultaneous stereodifferentiation of all aromarelevant 4(5) alkylsubstituted γ(δ)-lactones is described, using enantioselective multidimensional gas chromatography (MDG), and the column combination OV 1701/octakis(3-O-butyryl-2,6-di-O-pentyl)-γ-cyclodextrin. The method is applicated to the lactone flavour compounds of fruits, indicating the advance to the analytical differentiation between “natural” and “nature-identical” aromas. Modified cyclodextrins are also proved to be powerful tools in the chirospecific CGC analysis of monoterpenoid constituents of essential oils. Optical purity control is discussed as an indicator for their natural origin. 相似文献
1000.
Levels of RNA polymerase activities during growth,encystment and germination ofPhysarum polycephalum
Summary Two RNA polymerases, enzyme A and enzyme B, were prepared fromPhysarum plasmodia. They are not located in the cytosol. Isolated nuclei, however, contain only a fraction of the total RNA polymerase activity: 1.5–19% depending on the nuclear preparation method.The level of RNA polymerase B shows little variation at developmental stages of growth and encystment, or in cysts and during germination, whereas RNA polymerase A displays a marked transient decrease in activity during the stationary growth phase before encystment. 相似文献