ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Articles  (4)
  • Transport
  • Springer  (4)
  • American Meteorological Society
  • Springer Nature
  • Springer Science + Business Media
  • 2010-2014
  • 1995-1999  (4)
  • 1990-1994
  • 1970-1974
  • 1960-1964
  • 1999  (4)
Collection
  • Articles  (4)
Publisher
  • Springer  (4)
  • American Meteorological Society
  • Springer Nature
  • Springer Science + Business Media
Years
  • 2010-2014
  • 1995-1999  (4)
  • 1990-1994
  • 1970-1974
  • 1960-1964
Year
  • 1
    ISSN: 1432-072X
    Keywords: Key words Thiamin ; Biosynthesis ; Prokaryotes ; Transport ; Kinase ; Mechanism ; Structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Twelve genes involved in thiamin biosynthesis in prokaryotes have been identified and overexpressed. Of these, six are required for the thiazole biosynthesis (thiFSGH, thiI, and dxs), one is involved in the pyrimidine biosynthesis (thiC), one is required for the linking of the thiazole and the pyrimidine (thiE), and four are kinase genes (thiD, thiM, thiL, and pdxK). The specific reactions catalyzed by ThiEF, Dxs, ThiDM, ThiL, and PdxK have been reconstituted in vitro and ThiS thiocarboxylate has been identified as the sulfur source. The X-ray structures of thiamin phosphate synthase and 5-hydroxyethyl-4-methylthiazole kinase have been completed. The genes coding for the thiamin transport system (thiBPQ) have also been identified. Remaining problems include the cloning and characterization of thiK (thiamin kinase) and the gene(s) involved in the regulation of thiamin biosynthesis. The specific reactions catalyzed by ThiC (pyrimidine formation), and ThiGH and ThiI (thiazole formation) have not yet been identified.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    JBIC 4 (1999), S. 523-527 
    ISSN: 1432-1327
    Keywords: Key words Magnesium ; Transport ; Prokaryotes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract  Possessing the largest hydrated radius, the smallest ionic radius, and the highest charge density among the biologically relevant cations, Mg2+ provides an interesting problem for transport into living cells. Transport systems for Mg2+ have been characterized primarily in Salmonella typhimurium because the well-developed genetics of Gram-negative bacteria make cloning and studying the transporters a viable proposition. The CorA transport system is expressed constitutively and is the major Mg2+ transporter in Eubacteria and Archaea. It has three transmembrane domains, a uniquely large periplasmic domain, and no sequence homology to other proteins. The MgtE Mg2+ transporter also lacks sequence homology to other proteins, and it is unclear if Mg2+ transport is its primary function. The MgtA and MgtB Mg2+ transporters have sequence homology to P-type ATPases. They are more closely related to the mammalian Ca2+–ATPases than to the prokaryotic P-type ATPases. MgtA and MgtB mediate Mg2+ influx with, rather than against, the Mg2+ electrochemical gradient. Unlike corA and mgtE, the mgtA and mgtC/mgtB loci are regulated, being induced by the two-component regulatory system PhoP/PhoQ. PhoQ is a Mg2+ membrane sensor kinase that phosphorylates the transcription factor PhoP under Mg2+–limiting conditions. This factor then induces transcription of mgtA and mgtCB. MgtC, which is encoded by the first gene in the mgtCB operon, has no sequence homology to any known protein and is essential for S. typhimurium virulence in mice and macrophages, but does appear to be a Mg2+ transporter. The physiological roles of these Mg2+ transporters and their mechanisms are not yet completely clear, but initial data indicate that Mg2+ transporters are unique transport systems with unusual mechanisms for mediating Mg2+ movement through the membrane.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1432-1327
    Keywords: Key words Lanthanide ; Erythrocyte ; Transport ; Confocal laser scanning microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract  A novel method has been developed to visualize and follow the temporal course of lanthanide transport across the membrane into a single living erythrocyte. By means of confocal scanning microscopy and the optical section technique, the entry of lanthanide ions was followed by the fluorescence quenching of fluorescein isothiocyanate (FITC)-labeled membrane and cytosol. From the difference of the quenching kinetics of the whole section and the central area, the time for diffusion through the membrane and the diffusion in the extracellular and intracellular media can be deduced. To clarify the mechanism of lanthanide-induced fluorescence quenching of FITC-labeled erythrocytes and to ensure that this reaction can be used in this method, the reaction was investigated by steady-state fluorescence techniques. The results showed that the lanthanides strongly quenched the florescence emitted by FITC covalently bound to membrane proteins and cytosolic proteins. The static quenching mechanism is responsible for the fluorescence quenching of FITC-labeled proteins by Ln species. The quenching mechanism is discussed on the basis of complex formation. The dependence of fluorescence quenching on both ion size and the total orbital angular momentum L supports the complexation mechanism. The transport time across the membrane is strikingly correlated with Ln species and extracellular concentration. For a given concentration, the transport time of [Ln(cit)2]3– is much shorter than that of Ln3+, since they enter the cells via the anion channel. This is supported by the inhibition effect of 4,4′-diisothiocyanato-2,2′-stilbenendisulfonate on the transport of [Ln(cit)2]3–. On the other hand, the transport of free Ln3+ might be attributed to the enhanced permeability of erythrocytes owing to Ln3+ binding. These findings strongly demonstrate the existence of the non-internalization mechanism of Ln species uptake by erythrocytes.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Journal of computer-aided materials design 6 (1999), S. 283-309 
    ISSN: 1573-4900
    Keywords: Aluminum ; Growth ; Nucleation ; Predictive process engineering ; Reaction ; Semiconductor processing ; Thin films ; Transport ; Tungsten
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Two case studies are presented in order to highlight the status of materials modeling in semiconductor materials processing, as well as some opportunities in the area. Both case studies involve programmed rate chemical vapor deposition (PRCVD), which is a CVD process in which conditions are systematically changed during deposition in order to enhance either processing properties or resulting film properties. In the tungsten study, quantitative simulations, based on fundamental transport and reaction modeling and a continuum film representation, are used to guide experiments that demonstrate how PRCVD can provide significantly greater throughput than conventional, constant rate CVD (CRCVD). We start the deposition process at a much higher temperature, compared to a CRCVD process, then decrease the temperature during deposition. We achieve throughput increases of about a factor of three, with more improvement clearly obtainable. In addition to the increase in throughput, the properties of the PRCVD films are equal to, or superior to, CRCVD films. The aluminum PRCVD case study demonstrates some opportunities for materials modeling. The protocols used are based upon qualitative models of nucleation and film growth, as there are no simulators that predict microstructure and film properties. Nevertheless, we demonstrate that the PRCVD processes, designed using qualitative models, can yield films with better properties than CRCVD processes. PRCVD films can have higher nuclei densities, higher fractions of (111) orientated Al, lower surface roughnesses, higher reflectivities, and resistivities closer to that of bulk aluminum. In general, PRCVD protocols provide degrees of freedom that can be used to improve processing or film properties. PRCVD may become much more important as films get thinner and interfaces become more important.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...