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1.
Expression of heat shock genes in Clostridium acetobutylicum 总被引:1,自引:0,他引:1
2.
Heinke Schnabel Edgar Schramm Ralf Schnabel Wolfram Zillig 《Molecular & general genetics : MGG》1982,188(3):370-377
Summary The partially circularly permuted, terminally redundant structure of the DNA of phage H has been confirmed by a cleavage map for the restriction enzymes PstI, ClaI, BglII, HindIII, and, partially, BamHI.Six variants of phage H have been isolated from 71 single plaques. Their genomes differ by several insertions, a deletion, and an inversion of a DNA segment with a minimal length of 11 kb. The inversion occurs with high frequency in variants carrying at the flanks of the invertible DNA in verted repeats of a 1.8 kb DNA element which shares sequence homology with the DNA of H. halobium and may be involved in the extreme variability of its genome. 相似文献
3.
V D Michaelis I Neumann B Schulz W Nowak W K?cher R Michael P Heinke R Reding 《Endokrinologie》1975,64(3):257-268
In 8 female patients carbohydrate tolerance was proved by means of glucose infusion test 3 days after cholecystectomy. Parameters analyzed in portal and peripheral vein blood are compared with that of 47 healthy persons. All patients demonstrate a pathological carbohydrate tolerance after cholecystectomy, further characterized by an increased lipolysis, a paradoxical rise of HGH, a diminished insulin secretion during the early and increased IRI output in the second phase. There is a significant positive correlation between portal and peripheral vein IRI concentration despite the rising portalperipheral venous IRI difference with raised portal venous IRI concentration. Corresponding differences for proinsulin concentrations can be established in the early phase only. Relations existing between blood glucose and IRI are shown by multiple regression analysis. They suggest that the altitude of IRI concentration is determined by previous blood glucose concentration. 相似文献
4.
55 patients with pathological glucose tolerance received a long term treatment with buformin (200 mg daily). In 43 of the protodiabetics the duration of treatment was one year, in 29 of them two years and in 11 three years. The age of the patients was 38 years and the mean relative body weight was 118 per cent. The effect of buformin on glucose tolerance and insulin secretion was tested with the glucose infusion test before and after the periods of treatment. After one year we found in 58 per cent, after two years in 69 per cent and after three years in 64 per cent of the protodiabetics an improvement of glucose tolerance. In these groups the results showed a rise of the IRI in the low responder and a decrease of the IRI in the high responder. The good effects on glucose tolerance were not demonstrable in the compared groups with long-term treatment of diet only. 相似文献
5.
Schieb H Kratzin H Jahn O Möbius W Rabe S Staufenbiel M Wiltfang J Klafki HW 《The Journal of biological chemistry》2011,286(39):33747-33758
In this study, we report a detailed analysis of the different variants of amyloid-β (Aβ) peptides in the brains and the cerebrospinal fluid from APP23 transgenic mice, expressing amyloid precursor protein with the Swedish familial Alzheimer disease mutation, at different ages. Using one- and two-dimensional gel electrophoresis, immunoblotting, and mass spectrometry, we identified the Aβ peptides Aβ(1-40), -(1-42), -(1-39), -(1-38), -(1-37), -(2-40), and -(3-40) as well as minor amounts of pyroglutamate-modified Aβ (Aβ(N3pE)) and endogenous murine Aβ in brains from 24-month-old mice. Chemical modifications of the N-terminal amino group of Aβ were identified that had clearly been introduced during standard experimental procedures. To address this issue, we additionally applied amyloid extraction in ultrapure water. Clear differences between APP23 mice and Alzheimer disease (AD) brain samples were observed in terms of the relative abundance of specific variants of Aβ peptides, such as Aβ(N3pE), Aβ(1-42), and N-terminally truncated Aβ(2/3-42). These differences to human AD amyloid were also noticed in a related mouse line transgenic for human wild type amyloid precursor protein. Taken together, our findings suggest different underlying molecular mechanisms driving the amyloid deposition in transgenic mice and AD patients. 相似文献
6.
Delattre M Leidel S Wani K Baumer K Bamat J Schnabel H Feichtinger R Schnabel R Gönczy P 《Nature cell biology》2004,6(7):656-664
Centrosomes, the major microtubule-organizing centres (MTOCs) of animal cells, are comprised of a pair of centrioles surrounded by pericentriolar material (PCM). Early in the cell cycle, there is a single centrosome, which duplicates during S-phase to direct bipolar spindle assembly during mitosis. Although crucial for proper cell division, the mechanisms that govern centrosome duplication are not fully understood. Here, we identify the Caenorhabditis elegans gene sas-5 as essential for daughter-centriole formation. SAS-5 is a coiled-coil protein that localizes primarily to centrioles. Fluorescence recovery after photobleaching (FRAP) experiments with green fluorescent protein (GFP) fused to SAS-5 (GFP-SAS-5) demonstrated that the protein shuttles between centrioles and the cytoplasm throughout the cell cycle. Analysis of mutant alleles revealed that the presence of SAS-5 at centrioles is crucial for daughter-centriole formation and that ZYG-1, a kinase that is also essential for this process, controls the distribution of SAS-5 to centrioles. Furthermore, partial RNA-interference (RNAi)-mediated inactivation experiments suggest that both sas-5 and zyg-1 are dose-dependent regulators of centrosome duplication. 相似文献
7.
The scid defect affects the final step of the immunoglobulin VDJ recombinase mechanism 总被引:57,自引:0,他引:57
B A Malynn T K Blackwell G M Fulop G A Rathbun A J Furley P Ferrier L B Heinke R A Phillips G D Yancopoulos F W Alt 《Cell》1988,54(4):453-460
Abelson murine leukemia virus-transformed precursor B lymphocytes from scid (severe combined immunodeficient) mice, like A-MuLV transformants from normal mice, actively rearrange segments of their Ig heavy chain variable region gene locus during growth in culture. Targeting of recombination to appropriate segments appears normal in these lines as evidenced by initial rearrangement of sequences from within the D and JH locus to form aberrant "DJH" rearrangements and secondary rearrangement of sequences from within the VH locus to the aberrant "DJH" intermediates. A detailed analysis of the joints in these rearrangements indicates that the VDJ recombinase in scid pre-B cells can correctly recognize heptamernonamer signal sequences and perform precise endonucleolytic scissions at these sequences. We propose that the scid defect involves the inability of scid precursor lymphocytes to join correctly the cleaved ends of the coding strands of variable region gene segments. 相似文献
8.
J?rg Leitner S?ren Westerholz Bernhard Heinke Liesbeth Forsthuber Gabriele Wunderbaldinger Tino J?ger Doris Gruber-Schoffnegger Katharina Braun Jürgen Sandkühler 《PloS one》2013,8(8)
Adequate pain sensitivity requires a delicate balance between excitation and inhibition in the dorsal horn of the spinal cord. This balance is severely impaired in neuropathy leading to enhanced pain sensations (hyperalgesia). The underlying mechanisms remain elusive. Here we explored the hypothesis that the excitatory drive to spinal GABAergic neurons might be impaired in neuropathic animals. Transgenic adult mice expressing EGFP under the promoter for GAD67 underwent either chronic constriction injury of the sciatic nerve or sham surgery. In transverse slices from lumbar spinal cord we performed whole-cell patch-clamp recordings from identified GABAergic neurons in lamina II. In neuropathic animals rates of mEPSC were reduced indicating diminished global excitatory input. This downregulation of excitatory drive required a rise in postsynaptic Ca2+. Neither the density and morphology of dendritic spines on GABAergic neurons nor the number of excitatory synapses contacting GABAergic neurons were affected by neuropathy. In contrast, paired-pulse ratio of Aδ- or C-fiber-evoked monosynaptic EPSCs following dorsal root stimulation was increased in neuropathic animals suggesting reduced neurotransmitter release from primary afferents. Our data indicate that peripheral neuropathy triggers Ca2+-dependent signaling pathways in spinal GABAergic neurons. This leads to a global downregulation of the excitatory drive to GABAergic neurons. The downregulation involves a presynaptic mechanism and also applies to the excitation of GABAergic neurons by presumably nociceptive Aδ- and C-fibers. This then leads to an inadequately low recruitment of inhibitory interneurons during nociception. We suggest that this previously unrecognized mechanism of impaired spinal inhibition contributes to hyperalgesia in neuropathy. 相似文献
9.
Heinke Jäger María José Alencastro Martin Kaupenjohann Ingo Kowarik 《Plant and Soil》2013,368(1-2):629-640
Background and aims
Salinity is an increasing problem for agricultural production worldwide. Understanding how Na+ enters plants is important if reducing Na+ influx, a key component of the regulation of Na+ accumulation in plants and improving salt tolerance of crop plants, is to be achieved. Our previous work indicated that two distinct low-affinity Na+ uptake pathways exist in the halophyte Suaeda maritima. Here, we report the external NaCl concentration at which uptake switches from pathway 1 to pathway 2 and the kinetics of the interaction between external K+ concentration and Na+ uptake and accumulation in S. maritima in order to determine the roles of K+ transporters or channels in low-affinity Na+ uptake.Methods
Na+ influx, Na+ and K+ accumulations in S. maritima exposed to various concentrations of NaCl (0–200 mM) were analyzed in the absence and presence of the inhibitors TEA and Ba+ (5 mM TEA or 3 mM Ba2+) or KCl (0, 10 or 50 mM).Results
Our earlier proposal was confirmed and extended that there are two distinct low-affinity Na+ uptake pathways in S. maritima: pathway 1 might be mediated by a HKT-type transporter under low salinity conditions and pathway 2 by an AKT1-type channel or a KUP/HAK/KT type transporter under high salinity conditions. The external NaCl concentration at which two distinct low-affinity Na+ uptake switches from pathway 1 to pathway 2, the ‘turning point’, is between 90 and 95 mM. Over a short period (12 h) of Na+ and K+ treatments, a low concentration of K+ (10 mM) facilitated Na+ uptake by S. maritima under high salinity (100–200 mM NaCl), whether or not the plants had been subjected to a longer (3 d) period of K+ starvation. The kinetics suggests that low concentration of K+ (10 mM) might activate AKT1-type channels or KUP/HAK/KT-type transporters under high salinity (100–200 mM NaCl).Conclusions
The turning-point of external NaCl concentrations for the two low-affinity Na+ uptake pathways in Suaeda maritima is between 90 and 95 mM. A low concentration of K+ (10 mM) might activate AKT1 or KUP/HAK/KT and facilitate Na+ uptake under high salinity (100–200 mM NaCl). The kinetics of K+ on Na+ uptake and accumulation in S maritima are also consistent with there being two low-affinity Na+ uptake pathways. 相似文献10.
Heinke B Clauss W 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1999,169(2):148-156
The patch-clamp technique was employed in whole cells to analyze K+ conductances of amphibian colonic cells. Xenopus laevis colonic epithelium was dissected, and single epithelial cells were isolated using Ca2+-free solution and mild enzyme treatment. Vital epithelial cells had a round shape, and a distinction between apical and basolateral
poles was no longer possible. Their epithelial origin was, however, verified by antibodies against keratin. The average resting
potential of the colonocytes was −37.6 ± 1 mV (n = 220) and the resulting membrane current was strongly potassium selective. Further characterization of this conductance
was achieved by current-voltage relationship in the presence and absence of various K+ channel blockers. Barium and cesium showed pronounced voltage-dependent blockage, with interaction at about 35% inside the
pores. Lidocain, as well as quinine and quinidine also blocked, but with different kinetics and binding characteristics. Both
TEA and verapamil were ineffective. We also explored the effects of extra- (pHo) and intracellular pH (pHi) on the K+ conductance. An increase of pHo, as well as pHi, caused membrane hyperpolarization, and the shift of the current-voltage relationship indicates a stimulation of K+ channels by decreasing external and/or internal H+ concentration. The results provide the first whole-cell measurements on isolated amphibian colonic epithelial cells and demonstrate
the presence of various K+ channel types in this preparation.
Accepted: 15 January 1999 相似文献