Library

feed icon rss

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Review of international economics 2 (1994), S. 0 
    ISSN: 1467-9396
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Economics
    Notes: A leaning-against-the-wind intervention that has only a temporary effect on the exchange rate and that is not too aggressive can be shown analytically to yield positive expected profits to a central bank even when the exchange-rate process is nonstationary. These profits arise if there are some transitory shocks to the exchange rate. Furthermore, very aggressive intervention will yield positive expected profits eventually when there is a tendency for exchange rates to return to a long-run equilibrium level.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: Ferric citrate induces transcription of the ferric citrate transport genes fecABCDE without entering the cells of Escherichia coli K-12. Point mutants of the outer membrane-receptor protein FecA are affected in induction independent of the FecA transport activity, suggesting that FecA is directly involved in induction. Alignment of FecA with the other ferric siderophore receptors of E. coli reveals an N-terminal extension in FecA that is not found in the receptors whose synthesis is not induced by their cognate ferric siderophores. In this study, we show that excision of the N-terminal region abolished the inducing activity of FecA, but retained its transport activity. Overproduction of the N-terminal FecA fragment inhibited FecA-dependent induction, but not transport. Constitutive expression caused by C-terminally truncated FecR derivatives was not inhibited by the N-terminal FecA fragment. The N-terminal region of FecA was localized in the periplasm, which indicates that FecA probably interacts with FecR, which is involved in signal transduction across the cytoplasmic membrane. Transcription initiation of the fec transport genes required the Ton system, consisting of TonB, ExbB, and ExbD, and was inhibited by carbonylcyanide-m-chlorophenylhydrazone (CCCP) and 2,4-dinitrophenol (DNP), which dissipate the electrochemical potential of the cytoplasmic membrane. fec transcription of mutant fecA4, which displays constitutive fec transcription in the absence of TonB, was not affected by CCCP. The data support a model that proposes initiation of fec transport gene transcription by binding of ferric citrate to FecA. The transcription initiation signal is transferred across the outer membrane through the activity of the Ton system at the expense of the electrochemical potential of the cytoplasmic membrane. The N-terminus of FecA interacts in the periplasm with the C-terminus of FecR, through which the signal is transferred across the cytoplasmic membrane into the cytoplasm, where it increases the activity of the sigma factor FecI, which then directs the RNA polymerase to the fec promoter upstream of fecA.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: Citrate-dependent Fe3+ transport into Escherichia coli K-12 is induced by iron and citrate. The inducer is probably ferric dicitrate which does not have to be taken up into the cytoplasm to induce transcription of the fec transport genes. Two regulatory genes, fed and fecR, located upstream of the fecABCDE transport genes, are required for induction. We report that in vivo the chromosomally encoded Feel protein activates transcription of the fecA and fecB transport genes in response to ferric citrate and the FecR protein. Cells expressing chromosomally and plasmid-encoded truncated FecR derivatives no longer responded to ferric citrate and expressed the fec transport genes constitutively. The smallest active FecR derivative contained 59 amino acid residues as compared to the 317 residues of wild-type FecR. Constitutive induction was lower than induction of the FecR wild-type strain by ferric citrate. It is concluded that the N-terminal portion of FecR activates Feel and that the C-terminal portion of FecR responds to ferric citrate. Transcription of the fee transport genes is positively regulated by Feel and FecR and negatively regulated by the Fe2+-Fur repressor. Transcription activation and repression may occur independently of each other.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Archives of Insect Biochemistry and Physiology 29 (1995), S. 11-23 
    ISSN: 0739-4462
    Keywords: cricket ; HPLC ; neuropeptide ; diuretic ; antidiuretic ; Malpighian tubule ; fluid secretion ; Mas-DP1 ; achetakinin ; Chemistry ; Food Science, Agricultural, Medicinal and Pharmaceutical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: In the Malpighian tubules of Acheta, the distal and middle segments are functionally and morphologically quite distinct (Spring and Kim, Mol Comp Physiol 12:130-145, 1993). Furthermore, they respond quite differently to corpora cardiaca (CC) homogenates, dibutyryl cAMP, and A23187 (Kim and Spring, J Insect Physiol 38:373-381, 1992). In this study we compared secretion by these two regions in response to Acheta and Romalea CC extracts, synthetic Manduca sexta diuretic peptide (Mas-DP1), and the family of synthetic myotropic peptides, the achetakinins, isolated from Acheta. Both Acheta and Romalea CC extracts had opposite effects on the two regions: mid-tubule secretion increased 3-fold whereas secretion by the distal segment declined 75-80%. Mas-DP1 increased secretion by the mid-tubule more than 3-fold and had no effect on the distal segment. All of the achetakinins decreased secretion by the distal tubule, with achetakinin 1 being least effective (55% inhibition) and achetakinin 5 being most effective (75% inhibition). Achetakinins 1 and 2 increased midtubule secretion by 3.7- and 3.3-fold, respectively, whereas the others had no effect on this region. Regarding HPLC fractions of CC extracts, in general the more hydrophilic fractions inhibited secretion by both distal and mid-tubules. The more hydrophobic fractions were nearly uniformly stimulatory when applied to the mid-tubule, and either inhibited secretion or had no effect on the distal region. The possible interpretations of these data and the implications towards future research are discussed. © 1995 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...