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  • 1
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 93 (1990), S. 4637-4641 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: By scanning the frequency of a single-mode dye laser crossed to a molecular beam of Cs2, we measured the excitation spectra of the C 1∏u–X 1∑+g transition by detecting selectively the molecular fluorescence and the emission from the dissociated Cs(62P3/2) atoms. Dependence of the predissociation on each vibrational and rotational level C 1∏u (v,J) is studied by comparing the intensities of molecular fluorescence and atomic emission. This predissociation is found to depend strongly on the vibrational quantum number v but weakly on the rotational quantum number J, and to occur most strongly around the v=3 level. The Franck–Condon factors between the RKR potential curve of the C 1∏u state and several repulsive potential curves are calculated, and are compared with the observed predissociation rates. The potential curve of the (2)3∑+u state, which is expected to be repulsive and to cause the predissociation through the spin–orbit interaction, is estimated to cross the potential curve of the C 1∏u state between the left turning points of v=1 and v=0 levels.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 94 (1991), S. 2600-2607 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: A Doppler-free polarization spectrum of the D 1Σ+u(v',J')–X 1Σ+g(v‘,J‘) transition has been observed, and the molecular constants of the D 1Σ+u state were determined. A remarkable variation of the vibrational spacing ΔGv with v', and large deviations of ΔGv from the fitted ΔGv curve for v'(approximately-greater-than)35 were analyzed. The potential curve of the perturbing state, which was identified as the bound (2)3Πu state, was estimated. By using an experimental setup where a collimated cesium beam is crossed at right angles by the laser beam, we measured the excitation spectra by monitoring separately the molecular fluorescence and the D2 or D1 atomic emission. We found that a predissociation of the D 1Σ+u state occurred for v'(approximately-greater-than)20, and the probability of predissociation increased with v'. The measured v' and J' dependence of the linewidth Γ showed a significant increase for v'(approximately-greater-than)25. The predissociation of the D 1Σ+u state is caused by a combination of spin–orbit interaction between the D 1Σ+u(v'J') and (2)3Π0u(e vJ') levels, and the L-uncoupling interaction between the bound (2)3Π0u(e vJ') and dissociative c 3Σ+u(N = J'J') levels.
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 240 (2004), S. 0 
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Vibrio parahaemolyticus thermostable direct haemolysin (TDH) is widely considered to be a pore-forming toxin. The protein has no significant homology to other known pore-forming toxins and its mechanism of action in vivo remains undefined. We demonstrate single channel pore-forming activity of V. parahaemolyticus TDH in planar lipid bilayers. Channel conductance ranged between 30–450 pS in 0.5 M KCl with a calculated cation selectivity (PK/PCl) of 2.7. Channels were formed in NaCl and choline-Cl with and without cholesterol present and in the presence of neutral or negatively charged phospholipids. Zinc ions did not block pore formation. Whilst various techniques have previously suggested that TDH is a pore-forming toxin, the data in this study provide direct single channel evidence and indicate several features of pore formation in synthetic phospholipid membranes.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    The @journal of organic chemistry 59 (1994), S. 488-490 
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Rat-1 cells exposed to Vibrio parahaemolyticus thermostable direct hemolysin (TDH) developed morphological changes including shrinkage of the cells and reduction in the size of nuclei. Cells either microinjected with TDH or transfected with the tdh gene also showed morphological changes similar to those induced by externally added toxin. Furthermore, TDH-exposed or tdh-transfected cells both showed chromatin condensation and DNA fragmentation which suggest cells undergoing apoptosis. In contrast, expression of a TDH mutant (R7) did not reveal any cytotoxic effects. We demonstrate that expressed TDH was distributed in the cytoplasm. The interleukin-1β-converting enzyme-related protease inhibitor ZVAD-FMK did not inhibit TDH cytotoxicity. Our results suggest that TDH can induce its cytotoxicity both from outside and from inside the cells and killed the cells through apoptosis.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The mechanism of action of Vibrio parahaemolyticus thermostable direct hemolysin (TDH) on cultured cells still remains unclear. We show that addition of osmotic stabilizers, such as polyethylene glycol and dextran, could not protect cultured rat embryonic fibroblast cells (Rat-1) against cytotoxicity induced by TDH, unlike their protection against the hemolytic activity of TDH. By contrast, 100 μM monodansylcadaverine, as well as the presence of 1 mM ethylene glycol-bis(β-aminoethyl ether)-N,N,N′,N′-tetraacetic acid (EGTA) in medium, protected the cells against cytotoxicity of TDH. Binding of TDH to Rat-1 cells and intracellular localization of TDH were affected by monodansylcadaverine and EGTA as analyzed by flow cytometry and confocal microscopy. On the hemolytic activity of TDH, monodansylcadaverine and EGTA had no effect. These results suggest that the mechanism of cytotoxicity of TDH on Rat-1 cells was different from that of hemolytic activity of TDH on red blood cells.
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  • 7
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 150 (1997), S. 0 
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Neutralizing monoclonal antibodies (mAbs) against Vibrio parahaemolyticus thermostable direct hemolysin (TDH) were used in probing the functional domains of this toxin. While pre-incubation of TDH with mAb 2A-13C inhibited further binding of TDH to erythrocytes, pre-incubation with another mAb 1–24 did not, indicating that mAb 1–24 epitope resides in a domain which is not involved in binding of TDH to erythrocytes. On the other hand, after binding to erythrocytes, TDH could react with mAb 1–24 but poorly with mAb 2A–13C, indicating that the mAb 2A–13C epitope is masked, possibly by erythrocyte surface. As both antibodies are TDH-specific and do not react with TRH (TDH-related hemolysin), we used TDH/TRH chimeric proteins to identify location of the epitopes for mAbs by inhibition ELISA as well as Western blotting. The results showed that the mAb 1–24 epitope resides on a region near the C-terminal of TDH (residues 99–139), while the mAb 2A–13C epitope resides on the N-terminal (residues 1–31). All these results suggested that, in TDH, the N-terminal region may be involved in binding process while the region near C-terminal may be involved in postbinding process.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: We constructed a physical map of the genomic DNA (5.1 Mb) for Vibrio parahaemolyticus strain AQ4673 by combining 17 adjacent NotI fragments. This map shows two circular replicons of 3.2 and 1.9 Mb. Pulsed-field gel electrophoresis (PFGE) of undigested genomic DNA revealed two bands of corresponding sizes. Analysis both by NotI digestion and by Southern blot of the two isolated bands confirmed the existence of two replicons. The presence of genes for 16S rRNA on both the replicons indicates that the replicons are chromosomes rather than megaplasmids. The two bands were also seen after PFGE of undigested genomic DNA of V. parahaemolyticus strains other than AQ4673, and of strains belonging to other Vibrio species, such as V. vulnificus, V. fluvialis and various serovars and biovars of V. cholerae. It is noteworthy that V. cholerae O1 strain 569B, a classical biovar, was also shown to have two replicons of 2.9 and 1.2 Mb, which does not agree with a physical map proposed in a previous study. Our results suggest that a two-replicon structure is common throughout Vibrio species.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1573-1979
    Keywords: fully balanced system ; analog circuits ; integrated circuits ; filters ; integrators ; amplifiers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract The system architectures, which allow a high performance fully balanced (FB) system based on ordinary/modified single-ended opamps to be implemented, are investigated and the basic and general requirements are formulated. Two new methods of an FB analog system design, which contribute towards achieving both a high performance IC system implementation and a great reduction of the design time are presented. It is shown that a single-ended system based on any type of opamp (rail-to-rail, constant g m , etc.), realized in any technology (CMOS, bipolar, BiCMOS, GaAs), can be easily and effectively converted to its FB counterpart in a very practical way. Using the proposed rules, any FB system implementation with opamps (data converter, modulator, filter, etc.) requires only a single-ended system version design and the drawbacks related to a conventional FB system design are avoided. The principles of the design are pointed out and they are verified by experimental results.
    Type of Medium: Electronic Resource
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  • 10
    Publication Date: 2018-06-25
    Description: Initial attachment and subsequent colonization of the intestinal epithelium comprise critical events allowing enteric pathogens to survive and express their pathogenesis. In enterotoxigenic Escherichia coli (ETEC), these are mediated by a long proteinaceous fiber termed type IVb pilus (T4bP). We have reported that the colonization factor antigen/III (CFA/III), an operon-encoded T4bP of ETEC, possesses a minor pilin, CofB, that carries an H-type lectin domain at its tip. Although CofB is critical for pilus assembly by forming a trimeric initiator complex, its importance for bacterial attachment remains undefined. Here, we show that T4bP is not sufficient for bacterial attachment, which also requires a secreted protein CofJ, encoded within the same CFA/III operon. The crystal structure of CofB complexed with a peptide encompassing the binding region of CofJ showed that CofJ interacts with CofB by anchoring its flexible N-terminal extension to be embedded deeply into the expected carbohydrate recognition site of the CofB H-type lectin domain. By combining this structure and physicochemical data in solution, we built a plausible model of the CofJ–CFA/III pilus complex, which suggested that CofJ acts as a molecular bridge by binding both T4bP and the host cell membrane. The Fab fragments of a polyclonal antibody against CofJ significantly inhibited bacterial attachment by preventing the adherence of secreted CofJ proteins. These findings signify the interplay between T4bP and a secreted protein for attaching to and colonizing the host cell surface, potentially constituting a therapeutic target against ETEC infection.
    Print ISSN: 0027-8424
    Electronic ISSN: 1091-6490
    Topics: Biology , Medicine , Natural Sciences in General
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