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Molecular organization and functional analysis of the CFA/II CS3 region of Enterotoxigenic Escherichia coli / Meachery Bhaskaran Jalajakumari.Jalajakumari, Meachery Bhaskaran January 1992 (has links)
1 v. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Microbiology and Immunology, 1992
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Characterization of the interaction of putrescine and the adenosine-3',5'-cyclic monophosphate-cAMP receptor protein complex in the regulation of the speC gene encoding ornithine decarboxylase in Escherichia coli /Busse, Leigh Anne, January 1988 (has links)
Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1988. / Vita. Abstract. Includes bibliographical references (leaves 51-60). Also available via the Internet.
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Structure and function of Escherichia coli SecA an essential component of the Sec translocase /Na, Bing. January 2007 (has links)
Thesis (Ph. D.)--Georgia State University, 2007. / Title from file title page. Phang C. Tai, committee chair; John Houghton Parjit Kaur, Chung-Dar Lu, committee members. Electronic text (148 p. : ill. (some col.)) : digital, PDF file. Description based on contents viewed Dec. 7, 2007. Includes bibliographical references (p. 125-140).
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Förekommer Stafylococcus aureus, Stafylococcus epidermidis, Escherichia coli, Streptococcus pyogenes och Bacillus sp : på allmänna ytor på avdelningen SET (ekonomi och teknik), Halmstad högskola?Restedt, Malou, Ala-Mikkula, Pia January 2007 (has links)
<p>Stafylococcus aureus, Stafylococcus epidermidis, Escherichia coli, Streptococcus</p><p>pyogenes och Bacillus sp. är bakterier som förekommer i vår normalflora eller runt om i</p><p>vår omgivning. De är i de allra flesta fall harmlösa men kan orsaka sjukdom ifall de</p><p>hamnar i t.ex. sår eller kontaminerar mat. Vissa av dessa bakterier har även en tendens att</p><p>utveckla resistens mot antibiotika, infektioner orsakade av resistenta bakterier kan bli</p><p>allvarliga och väldigt svåra att behandla. Detta är det främsta skälet till varför vi har valt</p><p>att undersöka ifall de ovan nämnda bakterierna förkommer på avdelningen SET på</p><p>Halmstad högskola. För att kunna identifiera de bakterier vi fann använde vi oss av en rad</p><p>olika biokemiska tester och resistensbestämningen utfördes bl.a. med hjälp av en PCR</p><p>körning. Vi fann alla de bakterier vi sökte efter förutom S. pyogenes och ingen av de</p><p>funna visade på någon resistens mot antibiotika.</p>
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The discriminator domain : does it reside at the C-terminus or the N-terminus of Escherichia coli Lon?Miller, Darcey L. 27 August 2001 (has links)
The mechanisms of substrate recognition by regulatory proteases are not well
understood. Presently, two opposing models have arisen to describe E. coil Lon's ability
to discriminate between substrates: one suggests the N-terminus involvement while the
second suggests the C-terminus involvement. In this project, the role of the C-terminal
domain as it relates to the recognition of Lon's normal physiological substrates RcsA, an
activator of colanic acid capsular polysaccharide, and SulA, an inhibitor of cell division,
was addressed. Using site-directed mutagenesis, five mutations in Lon (R537G, E538A,
GS40W, R542G, R542P) were isolated. Their phenotypic impact was either similar in
character to wildtype Lon (R537G, E538A) or ��lon cells (G540W, R542G, R542P). The
stabilization of both RcsA and SulA based on phenotypic assays and immunological
detection of lon* strains (G540W, R542G, R542P) suggests the C-terminal domain may
be involved in substrate degradation as opposed to discriminator activity. / Graduation date: 2002
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Characterization and engineering of the twin-arginine translocation pathway of Escherichia coliErcek, Danielle Tullman, January 1900 (has links) (PDF)
Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.
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Förekommer Stafylococcus aureus, Stafylococcus epidermidis, Escherichia coli, Streptococcus pyogenes och Bacillus sp : på allmänna ytor på avdelningen SET (ekonomi och teknik), Halmstad högskola?Restedt, Malou, Ala-Mikkula, Pia January 2007 (has links)
Stafylococcus aureus, Stafylococcus epidermidis, Escherichia coli, Streptococcus pyogenes och Bacillus sp. är bakterier som förekommer i vår normalflora eller runt om i vår omgivning. De är i de allra flesta fall harmlösa men kan orsaka sjukdom ifall de hamnar i t.ex. sår eller kontaminerar mat. Vissa av dessa bakterier har även en tendens att utveckla resistens mot antibiotika, infektioner orsakade av resistenta bakterier kan bli allvarliga och väldigt svåra att behandla. Detta är det främsta skälet till varför vi har valt att undersöka ifall de ovan nämnda bakterierna förkommer på avdelningen SET på Halmstad högskola. För att kunna identifiera de bakterier vi fann använde vi oss av en rad olika biokemiska tester och resistensbestämningen utfördes bl.a. med hjälp av en PCR körning. Vi fann alla de bakterier vi sökte efter förutom S. pyogenes och ingen av de funna visade på någon resistens mot antibiotika.
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The function and structural characteristics of conserved regions within Escherichia Coli small subunit ribosomal RNAAlmehdi, Mirza A. 10 September 1991 (has links)
Ribosomes are multicomponent macromolecular particles and
are essential for the survival of cells in all organisms. The ribosome's
universal function is to catalyze polypeptide synthesis through
translation of mRNA transcripts. Ribosomes from Escherichia coli,
eubacterial organisms, have a sedimentation coefficient of 70S and are
composed of 30S and 50S ribonucleoprotein subunits. The small
ribosomal subunit is an assembly of 21 different proteins and a 16S
ribosomal RNA. Within the 16S rRNA there are a few short stretches of
universally conserved sequences spanning positions 517-533, 1394-1408,
and 1492-1506. Clear functions for these sequence zones have not yet
been assigned.
Here I report a kinetic analysis of these highly conserved regions
in the 16S rRNA and within the 30S ribosomal subunits. Binding affinity
was measured in experiments that were based on protection from
nuclease 51 digestion of short oligodeoxynucleotides hybridized to the
designated regions. DNAs hybridized to regions 1400 and 1500 show
significant differences in the apparent dissociation constants when
measured in 30S particles as opposed to those found for 16S rRNA.
Region 525 showed no difference in kinetic behavior.
To further elucidate the functional and structural role played by
the region centered about C1400 in 16S rRNA, a four nucleotide deletion
was constructed within this region. The deletion was introduced by
direct RNA manipulation using DNA/RNA hybridization, RNase H
digestions, and ligation of the correct RNA fragments with T4 RNA
ligase. I improved ligation efficiency of large RNA molecules by
including a connector looped short DNA oligomer. Recycling products
through phenyl boronate agarose (PBA-30) column also improved the
efficiency of ligation.
The mutagenized 16S rRNA fully reassembles into 30 particles
and the altered 30S subunit possesses all of the normal ribosomal
proteins. Altered ribosomes were functional in in vitro translation of
MS2 mRNA. The altered ribosomes have lower translational activity
relative to controls. Here I present indirect evidence suggesting that the
decrease in the synthesis of MS2 coat proteins is the result of premature
termination.
The altered 16S RNA in ribosomes had an apparent dissociation
constants with DNA probes comparable to those found for normal 16S
rRNA. This suggest that the RNA is less flexible in the particle relative
to normal 30S subunits. The deletion at 1400 did not have any effect on
the physical properties of the 1500 region, as measured by DNA
hybridization. A minor, but significant, effect on the 525 region was
observed. A possible RNA/RNA interaction within the 30S particle is
proposed to account for this observation. / Graduation date: 1992
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Mass spectrometric studies on peptides and proteins : conformations of Escherichia coli Thioredoxin and its alkylated adducts studied by hydrogen/deuterium exchange and HPLC-electrospray ionization mass spectrometryKim, Moo-young 13 December 2000 (has links)
E. coli thioredoxin (TRX) was modified by the episulfonium ion derived
from S-(2-chloroethyl)glutathione (CEG) or S-(2-chloroethyl)cysteine (CEC). The
alkylation site was located at Cys-32, which was confirmed by tandem mass
spectrometry. Two forms of native TRX, Oxi- and Red-TRX, and two modified
TRXs, GS- and Cys-TRX, were examined by hydrogen/deuterium (H/D)
exchange reactions using electrospray ionization mass spectrometry (ESI-MS)
for the analysis.
Conformational dynamics during thermal denaturation were probed by H/D
exchange-in experiments. Under conditions in which the folded conformational
state is marginally stable, H/D exchange-in experiments resulted in mass spectra
differing in the number of incorporated deuteriums which indicates the presence
of two distinct populations of molecules. As the exchange-in time increased, the
population representing the unfolded state increased and the population for the
folded state decreased. The rate of conversion was used to estimate the rate
constant of unfolding. ESI mass spectra were also recorded as a function of
temperature without H/D exchange, and the observed bimodal charge state
distributions were analyzed in order to estimate melting temperatures. GS-TRX
showed increased resistance to hydrogen isotope exchange in comparison with
Red-TRX indicating that there were enhanced intramolecular interactions in the
former protein.
Pepsin digestion was performed on deuterated TRXs to analyze different
structural regions. The amount of deuterium incorporated was monitored with
peptic peptides from deuterated TRXs with different exchange-in incubation
periods. Deuterium levels of each peptide were plotted versus the exchange time
and fitted with a series of first-order rate terms. The regions 59-80 and 81-108 of
Oxi- and Red-TRX showed an EX1 mechanism as evidenced by two distinct
mass envelopes that appeared after a short incubation time in deuterated
solvent.
Tandem mass spectrometry (MS/MS) was carried out to obtain the
information on individual amide linkages. MS/MS data showed generally
excellent correlations with the exchange rate constants from published NMR data
on Oxi- and Red-TRXs. Two residues, Ile-75 and Ala-93 in GS-TRX indicated the
most probable sites responsible for induced H-bonding by the attached
glutathionyl group, which was consistent with the energy minimized structure
predicted by AMBER force field constants. / Graduation date: 2001
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Serotipificación de Escherichia coli enteropatógena (EPEC) en cuadros diarreicos agudos de niños menores de cinco años : Hospital Nacional Docente Madre-Niño San Bartolomé, noviembre 2000-marzo 2001Alarcón Bendezú, Ruth Ysabel, Li Huasasquiche, Jessica Giovanna January 2007 (has links)
Con el objetivo de determinar los serotipos más frecuente de Escherichia coli Enteropatógena (EPEC) en los cuadros diarreicos agudos de niños menores de cinco años, se diseñó una investigación de tipo descriptivo, transversal, y observacional. La población de estudio estuvo constituida por 251 niños tratados en forma ambulatoria en el Hospital Nacional Docente Madre Niño “San Bartolomé” durante los meses de noviembre del 2000 a marzo del 2001. Se encontró 42 % (105 casos) de coprocultivos positivos a bacterias enteropatógenas, siendo Escherichia coli enteropatógena (EPEC) con 29,2 % (35 casos), la segunda causa más frecuente después de Shigella sp. Los serotipos de EPEC encontrados fueron: 9 casos del O119, 8 casos de O26, 6 casos del O55 y 2 casos del O86. Se concluye que lo serotipos más frecuentes de EPEC en los cuadros diarreicos agudos de niños menores de cinco años fueron el O119 y el O26.
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