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991.
R. Huber Josef Stöhr Sabine Hohenhaus Reinhard Rachel Siegfried Burggraf Holger W. Jannasch Karl O. Stetter 《Archives of microbiology》1995,164(4):255-264
From a hydrothermal vent site off the Mexican west coast (20°50′N, 109°06′W) at a depth of 2,600 m, a novel, hyperthermophilic,
anaerobic archaeum was isolated. Cells were round to slightly irregular cocci, 1.2–2.5 μm in diameter and were motile by means
of a tuft of flagella. The new isolate grew between 60 and 93°C (optimum: 85°C), from pH 3.5 to 9 (optimum: pH 6.7), and from
0.8 to 8% NaCl (optimum: 2%). The isolate was an obligate organotroph, using chitin, yeast extract, meat extract, and peptone
for growth. Chitin was fermented to H2, CO2, NH3, acetate, and formate. H2S was formed in the presence of sulfur. The chitinoclastic enzyme system was oxygen-stable, cell-associated, and inducible
by chitin. The cell wall was composed of a surface layer of hex- americ protein complexes arranged on a p6 lattice. The core
lipids consisted of glycerol diphytanyl diethers and acyclic and cyclic glycerol diphytanyl tetraethers. The G+C content was
46.5 mol%. DNA/DNA hybridization and 16S rRNA sequencing indicated that the new isolate belongs to the genus Thermococcus, representing a new species, Thermococcus chitonophagus. The type strain is isolate GC74, DSM 10152.
Received: 8 May 1995 / Accepted: 26 June 1995 相似文献
992.
Sandrine Salmon Rémi Lemoine Aziz Jamai Sabine Bouché-Pillon Jean Christophe Fromont 《Planta》1995,197(1):76-83
The mature petiole of celery is an organ with versatile sink/source capacities where sucrose and mannitol are unloaded from and reloaded into the phloem cells. Plasma-membrane vesicles were purified by twophase partitioning either from phloem strands isolated from mature petioles of celery (Apium graveolens L.) or from mature petioles devoid of vascular bundles. Both types of vesicle were comparable in purity (more than 86% of plasma-membrane origin), size (135 nm diameter) and orientation (72% right-side-out). Plasma-membrane vesicles from phloem tissues had a higher vanadate-sensitive ATPase activity than plasma-membrane vesicles from petioles. Plasma-membrane vesicles from phloem tissues accumulated mannitol and sucrose in response to an artificial proton-motive force, in agreement with the existence of proton/substrate carriers. Plasma-membrane vesicles from petioles devoid of vascular bundles accumulated only mannitol following application of an artificial proton-motive force. The data suggest the volvement of apoplasmic transport events. The pathway for sucrose uptake in storage parenchyma cells is discussed in the light of the available physiological data. 相似文献
993.
Sabine Engemann Elke Herfurth Ulrike Briesemeister Brigitte Wittmann-Liebold 《Journal of Protein Chemistry》1995,14(4):189-195
The ribosomal protein HS23 from the 30S subunit of the extreme halophilicHaloarcula marismortui, belonging to the group of archaea, was isolated either by RP-HLPLC or two-dimensional polyacrylamide gel electrophoresis. The complete amino acid sequence was determined by automated N-terminal microsequencing. The protein consists of 123 residues with a corresponding molecular mass of 12,552 Da as determined by electrospray mass spectroscopy; the pI is 11.04. Homology studies reveal similarities to the eukaryotic ribosomal protein S8 fromHomo sapiens, Rattus norvegicus, Leishmania major, andSaccharomyces cerevisiae.Abbreviations
H. marismortui
Haloarcula marismortui
- PVDF
polyvinylidene difluoride
- PTH
phenylthiohydantoin
- RP-HPLC
reversed-phase high-performance liquid chromatography
- TFA
trifluoro acetic acid
- TP30
total protein mixture from the 30S ribosomal subunit ofH. marismortui 相似文献
994.
An Essential Role for CD44 Variant Isoforms in Epidermal Langerhans Cell and Blood Dendritic Cell Function 总被引:13,自引:0,他引:13
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Johannes M. Weiss Jonathan Sleeman Andreas C. Renkl Henning Dittmar Christian C. Termeer Sabine Taxis Norma Howells Martin Hofmann Gabriele Khler Erwin Schpf Helmut Ponta Peter Herrlich Jan C. Simon 《The Journal of cell biology》1997,137(5):1137-1147
Upon antigen contact, epidermal Langerhans cells (LC) and dendritic cells (DC) leave peripheral organs and home to lymph nodes via the afferent lymphatic vessels and then assemble in the paracortical T cell zone and present antigen to T lymphocytes. Since splice variants of CD44 promote metastasis of certain tumors to lymph nodes, we explored the expression of CD44 proteins on migrating LC and DC. We show that upon antigen contact, LC and DC upregulate pan CD44 epitopes and epitopes encoded by variant exons v4, v5, v6, and v9. Antibodies against CD44 epitopes inhibit the emigration of LC from the epidermis, prevent binding of activated LC and DC to the T cell zones of lymph nodes, and severely inhibit their capacity to induce a delayed type hypersensitivity reaction to a skin hapten in vivo. Our results demonstrate that CD44 splice variant expression is obligatory for the migration and function of LC and DC. 相似文献
995.
Characterization of the interaction between the baculovirus replication factors LEF-1 and LEF-2. 总被引:5,自引:3,他引:2
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The Autographa californica multinucleocapsid nuclear polyhedrosis virus has six genes required and three genes stimulatory for transient DNA replication. We demonstrate that the products of two of these genes, LEF-1 and LEF-2, interact in both two-hybrid assays using Saccharomyces cerevisiae and glutathione S-transferase fusion affinity assays. Using yeast-two-hybrid assays, we mapped the interaction domain of LEF-2 to amino acids between positions 20 and 60. Extensive deletion analyses of LEF-1 failed to reveal a delimited interaction domain, suggesting that there may be essential secondary structural elements that are inactivated by these deletions. All clones expressing LEF-1 and LEF-2 that were unable to interact also failed to support significant levels of transient DNA replication, suggesting that this interaction is required for DNA replication. Sequence analysis of LEF-1 revealed a primase-like motif, WVVDAD. When this motif was mutated to WVVQAD, LEF-1 no longer supported transient DNA replication. 相似文献
996.
Sabine Münch-Garthoff Jean-Marc Neuhaus Thomas Boller Birgit Kemmerling Karl-Heinz Kogel 《Planta》1997,201(2):235-244
997.
We isolated the gene encoding lysine-ketoglutarate reductase (LKR, EC 1.5.1.8) and saccharopine dehydrogenase (SDH, ED 1.5.1.9) from an Arabidopsis thaliana genomic DNA library based on the homology between the yeast biosynthetic genes encoding SDH (lysine-forming) or SDH (glutamate-forming) and Arabidopsis expressed sequence tags. A corresponding cDNA was isolated from total Arabidopsis RNA using RT-PCR and 5 and 3 Race. DNA sequencing revealed that the gene encodes a bifunctional protein with an amino domain homologous to SDH (lysine-forming), thus corresponding to LKR, and a carboxy domain homologous to SDH (glutamate-forming). Sequence comparison between the plant gene product and the yeast lysine-forming and glutamate-forming SDHs showed 25% and 37% sequence identity, respectively. No intracellular targeting sequence was found at the N-terminal or C-terminal of the protein. The gene is interrupted by 24 introns ranging in size from 68 to 352 bp and is present in Arabidopsis in a single copy. 5 sequence analysis revealed several conserved promoter sequence motifs, but did not reveal sequence homologies to either an Opaque 2 binding site or a Sph box. The 3-flanking region does not contain a polyadenylation signal resembling the consensus sequence AATAAA. The plant SDH was expressed in Escherichia coli and exhibited similar biochemical characteristics to those reported for the purified enzyme from maize. This is the first report of the molecular cloning of a plant LKR-SDH genomic and cDNA sequence. 相似文献
998.
999.
Haase Hannelore Bartel Sabine Karczewski Peter Morano Ingo Krause Ernst-Georg 《Molecular and cellular biochemistry》1996,163(1):99-106
In canine myocardium, the -subunit of the L-type Ca2+ channel is phosphorylated by cAMP dependent protein kinase in vitro as well as in vivo (Haase et al. FEBS Lett 335: 217–222, 1993). We have assessed the identity of the -subunit as well as its in vivo phosphorylation in representative experimental groups of catecholamine-challenged canine hearts. Adrenergic stimulation by high doses of both noradrenaline and isoprenaline induced rapid (within 20 sec) and nearly complete phosphorylation of the Ca2+ channel -subunit. Phosphorylation in vivo was about 4-fold higher as compared to untreated controls. When related to catecholamine-depleted (reserpine-treated) hearts noradrenaline and isoprenaline increased the in vivo phosphorylation of the -subunit even 8-fold. This phosphorylation correlated positively with tissue levels of cAMP, endogenous particulated cAMP-dependent protein kinase (PKA) and the rate of contractile force development dP/dtmax. The results imply the involvement of a PKA-mediated phosphorylation of the Ca2+ channel -subunit in the adrenergic stimulation of intact canine myocardium. 相似文献
1000.
Bartel Sabine Karczewski Peter Krause Ernst-Georg 《Molecular and cellular biochemistry》1996,163(1):31-38
The postnatal alterations of the composition of a subunit isoforms (Gic, G i3 Go, and Gq of G proteins, the adenylyl cyclase activity as well as of cAMP-regulated phosphoproteins e.g. troponin and phospholamban were investigated in the ventricular tissue of 1, 7, 30 days old rats. Quantitative immunodetection revealed a 5.7-fold decrease in Gi3 at 30th postnatal day compared with the postnatal day 1 and up to 15-fold at 4 months. The amounts of Gq and G as well as the G subunits were found to be higher in the earlier life period compared to the adult. In contrast, the content of Gs was uneffected by the developmental state. Basal adenylyl cyclase activity (pmoles cAMP/min × mg protein) increased from 30.9 ± 5.0, 36.8 ± 5.0 to 63.9 ± 5.9 at 1st, 7th and 30th postnatal day, respectively. Isoprenaline (100 M) enhanced the activity of adenylyl cyclase from day 1, 7–30 from 46.2 ± 7.0, 79.1 ± 9.2 to 120.5 ± 7.2, respectively. The effects of forskolin and NaF on adenylyl cyclase activity was found to be not influenced within the first postnatal month. Furthermore, a developmentally controlled expression of cardiac troponin I was observed (6-fold from the first to the 28th postnatal day) whereas the level of phospholamban was found to be age-independent.In conclusion, there is an increase in the efficiency of the -adrenergic signal transfer mainly caused by a reduction of the inhibitiory G proteins and a dominance of the Gs-linked pathway in the postnatal rat heart. Furthermore the developmentally controlled expression of troponin I might be of functional importance in the cAMP-supported relaxation. Additionally, altered Gq, Go and G pattern of the developing rat ventricle may play a role in the observed change of -adrenerg-mediated heart contractility as well as in cardiac differentiation and growth processes. 相似文献