bluuebunny/crossref_metadata_2025_split huggingface dataset:
Intradiscal Thermal Annuloplasty for Discogenic Pain: An Outcome Study
Authors: Mekhail Nagy , Kapural Leonardo 
Published: June 2004

Abstract:Objectives:  Published studies of intradiscal thermal annuloplasty (IDTA) have shown at most 50% pain relief as an improved outcome with little focus on functional improvement in the treatment of discogenic pain. Previous studies have used a number of criteria for patient selection including low back pain unresponsive to conservative care, no compressive radiculopathy, positive provocative discography and absence of previous surgery at the same symptomatic level. The purpose of present study is to examine the hypothesis that additional inclusion criteria for patient selection such as disc height, absence of degenerative disc disease (DDD) in untreated discs, absence of herniated nucleus pulposus or lumbar canal stenosis may improve the outcome of treatment.Methods:  In this prospective case‐series study additional criteria of patient selection were introduced, namely disc height of at least 50%, no lumbar canal stenosis, one or two levels of DDD, no evidence of nucleus pulposus herniation on magnetic resonance image. Thirty‐four patients were enrolled in the study and 32 of them were followed over a period of 12 months. The visual analog scale (VAS) pain score and seven activities of daily living (ADLs) were followed and reported on a scale from 0 to 10.Results:  Sustained decrease of the VAS pain scores was observed from 3 to 12 months following IDTA. ADLs improved in all patients between 3 and 12 months post‐treatment. Patients in the Bureau of Workers Compensation (BWC) group had a higher VAS score but showed the same level of improvement in ADLs as compared to commercial insurance or self‐pay patients. In the non‐BWC patient group an average VAS pain score decrease of more than 6 points on a 10‐point scale was reported at 6 to 12 months following IDTA.Conclusions:  We found dramatic improvement of pain scores and ADLs following IDTA when strict patient selection was applied. We believe that IDTA is an effective, minimally invasive treatment for discogenic pain in properly selected patients.
The Decrease in FlaA Observed in a
flaB
Mutant of
Borrelia burgdorferi
Occurs Posttranscriptionally
Authors: Motaleb M. A. , Sal Melanie S. , Charon Nyles W. 
Published: June 2004

ABSTRACT

The Lyme disease bacterium
Borrelia burgdorferi
is a motile spirochete with a flat-wave morphology. The periplasmic flagella, which are situated between the outer membrane sheath and cell cylinder, are essential for both the cell's wavy shape and motility. Here we focus on the structure and regulation of its periplasmic flagella. Previous studies have suggested that the periplasmic flagella consist of a polymer of the major filament protein FlaB and a minor protein, FlaA. We used immunoprecipitation methodology to present further evidence that FlaA is indeed a flagellar protein. In addition, in contrast to FlaA of the spirochete
Brachyspira hyodysenteriae
,
B. burgdorferi
FlaA did not impact the overall helical shape of the periplasmic flagella. We have previously shown that
B. burgdorferi
lacks the sigma factor-dependent cascade control of motility gene transcription found in other bacteria. To begin to understand motility gene regulation in
B. burgdorferi
, we examined the effects of an insertion mutation in
flaB
on the amounts of proteins encoded by motility genes. Of several motility gene-encoded proteins examined, only the amount of FlaA was decreased in the
flaB
mutant; it was 13% compared to the wild-type amount. Real-time reverse transcriptase PCR analysis indicated that this inhibition was not the result of a decrease in
flaA
mRNA. In addition, protein stability analysis suggested that FlaA was turned over in the
flaB
mutant. Our results indicate that the lack of FlaB negatively influences the amount of FlaA found in the cell and that this effect is at the level of either translational control or protein turnover.
Characterization and Functional Analysis of thepoxBGene, Which Encodes Pyruvate Oxidase inLactobacillus plantarum
Authors: Lorquet Frédérique , Goffin Philippe , Muscariello Lidia , Baudry Jean-Bernard , Ladero Victor , Sacco Margherita , Kleerebezem Michiel , Hols Pascal 
Published: June 2004

ABSTRACTThe pyruvate oxidase gene (poxB) fromLactobacillus plantarumLp80 was cloned and characterized. Northern blot and primer extension analyses revealed that transcription ofpoxBis monocistronic and under the control of a vegetative promoter.poxBmRNA expression was strongly induced by aeration and was repressed by glucose. Moreover, Northern blotting performed at different stages of growth showed thatpoxBexpression is maximal in the early stationary phase when glucose is exhausted. Primer extension and in vivo footprint analyses revealed that glucose repression ofpoxBis mediated by CcpA binding to thecresite identified in the promoter region. The functional role of the PoxB enzyme was studied by using gene overexpression and knockout in order to evaluate its implications for acetate production. Constitutive overproduction of PoxB inL. plantarumrevealed the predominant role of pyruvate oxidase in the control of acetate production under aerobic conditions. The ΔpoxBmutant strain exhibited a moderate (20 to 25%) decrease in acetate production when it was grown on glucose as the carbon source, and residual pyruvate oxidase activity that was between 20 and 85% of the wild-type activity was observed with glucose limitation (0.2% glucose). In contrast, when the organism was grown on maltose, thepoxBmutation resulted in a large (60 to 80%) decrease in acetate production. In agreement with the latter observation, the level of residual pyruvate oxidase activity with maltose limitation (0.2% maltose) was less than 10% of the wild-type level of activity.
The Type III Secreted Protein BopD in
Bordetella bronchiseptica
Is Complexed with BopB for Pore Formation on the Host Plasma Membrane
Authors: Nogawa Hisashi , Kuwae Asaomi , Matsuzawa Takeshi , Abe Akio 
Published: June 2004

ABSTRACT

The cytotoxicity of
Bordetella bronchiseptica
to infected cells is known to be dependent on a
B
.
bronchiseptica
type III secretion system. Although BopB, BopN, BopD, and Bsp22 have been identified as type III secreted proteins, these proteins remain to be characterized. In this study, in order to clarify the function of BopD during
Bordetella
infection, a BopD mutant was generated. Although secretion of BopD into the culture supernatant was completely abolished by the
bopD
mutation, the secretion of other type III secreted proteins was not affected by this mutation. It has been reported that severe cytotoxicity, including cell detachment from the substrata, and release of lactate dehydrogenase (LDH) into the supernatant are induced in L2 cells by wild-type
B
.
bronchiseptica
infection, and these phenotypes are dependent on the type III secretion system. In contrast, neither cell detachment nor LDH release was induced in L2 cells infected with the BopD mutant. Furthermore, the hemolytic activity of the BopD mutant was greatly impaired compared with that of the wild-type strain. On the basis of the results of coimmunoprecipitation assays with anti-BopB antibodies, we conclude that BopD has the ability to associate with BopB. Finally, we show that the BopD-BopB complex is responsible for the pore formation in the host plasma membrane that functions as the conduit for the transition of effector proteins into host cells.
Genetic Characterization of a Multicomponent Signal Transduction System Controlling the Expression of Cable Pili in
Burkholderia cenocepacia
Authors: Tomich Mladen , Mohr Christian D. 
Published: June 2004

ABSTRACT

Cable pili are peritrichous organelles expressed by certain strains of
Burkholderia cenocepacia
, believed to facilitate colonization of the lower respiratory tract in cystic fibrosis patients. The
B. cenocepacia cblBACDS
operon encodes the structural and accessory proteins required for the assembly of cable pili, as well as a gene designated
cblS
, predicted to encode a hybrid sensor kinase protein of bacterial two-component signal transduction systems. In this study we report the identification of two additional genes, designated
cblT
and
cblR
, predicted to encode a second hybrid sensor kinase and a response regulator, respectively. Analyses of the deduced amino acid sequences of the
cblS
and
cblT
gene products revealed that both putative sensor kinases have transmitter and receiver domains and that the
cblT
gene product has an additional C-terminal HPt domain. Mutagenesis of the
cblS
,
cblT
, or
cblR
gene led to a block in expression of CblA, the major pilin subunit, and a severe decrease in
cblA
transcript abundance. Using transcriptional fusion analyses, the decrease in the abundance of the
cblA
transcript in the
cblS
,
cblT
, and
cblR
mutants was shown to be due to a block in transcription from the
cblB
-proximal promoter, located upstream of the
cblBACDS
operon. Furthermore, ectopic expression of either
cblS
or
cblR
in wild-type
B. cenocepacia
strain BC7 led to a significant increase, while ectopic expression of
cblT
resulted in a dramatic decrease, in abundance of the CblA major pilin and the
cblA
transcript. Our results demonstrate that the
B. cenocepacia cblS
,
cblT
, and
cblR
genes are essential for cable pilus expression and that their effect is exerted at the level of transcription of the
cblBACDS
operon. These findings are consistent with the proposed function of the
cblSTR
gene products as a multicomponent signal transduction pathway controlling the expression of cable pilus biosynthetic genes in
B. cenocepacia
.
Expression Analysis of a Highly Adherent and Cytotoxic Small Colony Variant of
Pseudomonas aeruginosa
Isolated from a Lung of a Patient with Cystic Fibrosis
Authors: von Götz Franz , Häussler Susanne , Jordan Doris , Saravanamuthu Senthil Selvan , Wehmhöner Dirk , Strüßmann André , Lauber Joerg , Attree Ina , Buer Jan , Tümmler Burkhard , Steinmetz Ivo 
Published: June 2004

ABSTRACT

The heterogeneous environment of the lung of the cystic fibrosis (CF) patient gives rise to
Pseudomonas aeruginosa
small colony variants (SCVs) with increased antibiotic resistance, autoaggregative growth behavior, and an enhanced ability to form biofilms. In this study, oligonucleotide DNA microarrays were used to perform a genome-wide expression study of autoaggregative and highly adherent
P. aeruginosa
SCV 20265 isolated from a CF patient's lung in comparison with its clonal wild type and a revertant generated in vitro from the SCV population. Most strikingly, SCV 20265 showed a pronounced upregulation of the type III protein secretion system (TTSS) and the respective effector proteins. This differential expression was shown to be biologically meaningful, as SCV 20265 and other hyperpiliated and autoaggregative SCVs with increased TTSS expression were significantly more cytotoxic for macrophages in vitro and were more virulent in a mouse model of respiratory tract infection than the wild type. The observed cytotoxicity and virulence of SCV 20265 required
exsA
, an important transcriptional activator of the TTSS. Thus, the prevailing assumption that
P. aeruginosa
is subject to selection towards reduced cytotoxicity and attenuated virulence during chronic CF lung infection might not apply to all clonal variants.
The Arginine Regulatory Protein Mediates Repression by Arginine of the Operons Encoding Glutamate Synthase and Anabolic Glutamate Dehydrogenase in
Pseudomonas aeruginosa
Authors: Hashim Shehab , Kwon Dong-Hyeon , Abdelal Ahmed , Lu Chung-Dar 
Published: June 2004

ABSTRACT

The arginine regulatory protein of
Pseudomonas aeruginosa
, ArgR, is essential for induction of operons that encode enzymes of the arginine succinyltransferase (AST) pathway, which is the primary route for arginine utilization by this organism under aerobic conditions. ArgR also induces the operon that encodes a catabolic NAD
+
-dependent glutamate dehydrogenase (GDH), which converts
l
-glutamate, the product of the AST pathway, in α-ketoglutarate. The studies reported here show that ArgR also participates in the regulation of other enzymes of glutamate metabolism. Exogenous arginine repressed the specific activities of glutamate synthase (GltBD) and anabolic NADP-dependent GDH (GdhA) in cell extracts of strain PAO1, and this repression was abolished in an
argR
mutant. The promoter regions of the
gltBD
operon, which encodes GltBD, and the
gdhA
gene, which encodes GdhA, were identified by primer extension experiments. Measurements of β-galactosidase expression from
gltB
::
lacZ
and
gdhA
::
lacZ
translational fusions confirmed the role of ArgR in mediating arginine repression. Gel retardation assays demonstrated the binding of homogeneous ArgR to DNA fragments carrying the regulatory regions for the
gltBD
and
gdhA
genes. DNase I footprinting experiments showed that ArgR protects DNA sequences in the control regions for these genes that are homologous to the consensus sequence of the ArgR binding site. In silica analysis of genomic information for
P
.
fluorescens
,
P
.
putida
, and
P
.
stutzeri
suggests that the findings reported here regarding ArgR regulation of operons that encode enzymes of glutamate biosynthesis in
P
.
aeruginosa
likely apply to other pseudomonads.
Transcriptome Analysis of the ArgR Regulon inPseudomonas aeruginosa
Authors: Lu Chung-Dar , Yang Zhe , Li Wei 
Published: June 2004

ABSTRACTArginine metabolism in pseudomonads with multiple catabolic pathways for its utilization as carbon and nitrogen sources is of particular interest as the model system to study control of metabolic integration. We performed transcriptome analyses to identify genes controlled by the arginine regulatory protein ArgR and to better understand arginine metabolic pathways ofP.aeruginosa. We compared gene expression in wild-type strain PAO1 with that inargRmutant strain PAO501 grown in glutamate minimal medium in the presence and absence of arginine. Ten putative transcriptional units of 28 genes were inducible by ArgR and arginine, including all known ArgR-regulated operons under aerobic conditions. The newly identified genes include the putativeadcABoperon, which encodes a catabolic arginine decarboxylase and an antiporter protein, and PA0328, which encodes a hypothetical fusion protein of a peptidase and a type IV autotransporter. Also identified as members of the arginine network are the following solute transport systems: PA1971 (braZ) for branched-chain amino acids permease; PA2042 for a putative sodium:serine symporter; PA3934, which belongs to the family of small oligopeptide transporters; and PA5152-5155, which encodes components of an ABC transporter for a putative opine uptake system. The effect of arginine on the expression of these genes was confirmed bylacZfusion studies and by DNA binding studies with purified ArgR. Only five transcriptional units of nine genes were qualified as repressible by ArgR and arginine, with three operons (argF,carAB, andargG) in arginine biosynthesis and two operons (gltBDandgdhA) in glutamate biosynthesis. These results indicate that ArgR is important in control of arginine and glutamate metabolism and that arginine and ArgR may have a redundant effect in inducing the uptake systems of certain compounds.
Consequences of a Deletion in
dspA
on Transcript Accumulation in
Synechocystis
sp. Strain PCC6803
Authors: Tu Chao-Jung , Shrager Jeffrey , Burnap Robert L. , Postier Bradley L. , Grossman Arthur R. 
Published: June 2004

ABSTRACT

A sensor histidine kinase of
Synechococcus
sp. strain PCC7942, designated
nblS
, was previously identified and shown to be critical for the acclimation of cells to high-light and nutrient limitation conditions and to influence the expression of a number of light-responsive genes. The
nblS
orthologue in
Synechocystis
sp. strain PCC6803 is designated
dspA
(also called
hik33
). We have generated a
dspA
null mutant and analyzed global gene expression in both the mutant and wild-type strains under high- and low-light conditions. The mutant is aberrant for the expression of many genes encoding proteins critical for photosynthesis, phosphate and carbon acquisition, and the amelioration of stress conditions. Furthermore, transcripts from a number of genes normally detected only during exposure of wild-type cells to high-light conditions become partially constitutive in the low-light-grown
dspA
mutant. Other genes for which transcripts decline upon exposure of wild-type cells to high light are already lower in the mutant during growth in low light. These results suggest that DspA may influence gene expression in both a positive and a negative manner and that the
dspA
mutant behaves as if it were experiencing stress conditions (e.g., high-light exposure) even when maintained at near-optimal growth conditions for wild-type cells. This is discussed with respect to the importance of DspA for regulating the responses of the cell to environmental cues.
Structural Basis for Iron Binding and Release by a Novel Class of Periplasmic Iron-Binding Proteins Found in Gram-Negative Pathogens
Authors: Shouldice Stephen R. , Skene Robert J. , Dougan Douglas R. , Snell Gyorgy , McRee Duncan E. , Schryvers Anthony B. , Tari Leslie W. 
Published: June 2004

ABSTRACT

We have determined the 1.35- and 1.45-Å structures, respectively, of closed and open iron-loaded forms of
Mannheimia haemolytica
ferric ion-binding protein A.
M
.
haemolytica
is the causative agent in the economically important and fatal disease of cattle termed shipping fever. The periplasmic iron-binding protein of this gram-negative bacterium, which has homologous counterparts in many other pathogenic species, performs a key role in iron acquisition from mammalian host serum iron transport proteins and is essential for the survival of the pathogen within the host. The ferric (Fe
3+
) ion in the closed structure is bound by a novel asymmetric constellation of four ligands, including a synergistic carbonate anion. The open structure is ligated by three tyrosyl residues and a dynamically disordered solvent-exposed anion. Our results clearly implicate the synergistic anion as the primary mediator of global protein conformation and provide detailed insights into the molecular mechanisms of iron binding and release in the periplasm.
Spreading Factors of
Mycoplasma alligatoris
, a Flesh-Eating Mycoplasma
Authors: Brown D. R. , Zacher L. A. , Farmerie W. G. 
Published: June 2004

ABSTRACT

Mycoplasma alligatoris
causes lethal invasive disease of alligators and caimans. A homolog of the
nagH
gene, encoding a hyaluronidase secreted by
Clostridium perfringens
, and a
C
.
perfringens
hyaluronidase
nagI
or
nagK
pseudogene were discovered in the
M
.
alligatoris
genome. The
nagH
gene was detected by PCR in the closest relative of
M
.
alligatoris
,
Mycoplasma crocodyli
, but not in 40 other species representing the
Mycoplasma hominis
,
Mycoplasma pneumoniae
, and
Spiroplasma
phylogenetic clusters. The hyaluronidase activity in the cellular fraction of
M
.
alligatoris
and
M
.
crocodyli
SP4 broth cultures was equivalent to 10
−16
U of
Streptomyces hyalurolyticus
hyaluronidase CFU
−1
. Negligible activity was present in the cell-free supernatant fraction. No chondroitinase activity was detected. There is also a novel homolog of the
nanI
gene, which encodes a sialidase secreted by
C
.
perfringens
, in the
M
.
alligatoris
genome. The signature YRIP and SXDXGXTW motifs and catalytic residues of the clostridial sialidase are conserved in the mycoplasmal gene, but the leader sequence necessary for its secretion by
C
.
perfringens
is absent. The gene was not detected by PCR in any other mycoplasma. Potent cell-associated sialidase activity was present in
M
.
alligatoris
colonies on agar but not in the cell-free supernatants of broth cultures or in
M
.
crocodyli
. The presence of hyaluronidase and sialidase in
M
.
alligatoris
is consistent with the rapid invasiveness and necrotizing effects of this organism, and the lack of sialidase in
M
.
crocodyli
is consistent with its comparatively attenuated virulence. This genetic and biochemical evidence suggests that the spreading factors hyaluronidase and sialidase, a combination unprecedented in mycoplasmas, are the basis of the virulence of
M
.
alligatoris
.
Mutational Analysis of Transmembrane Regions 3 and 4 of SecY, a Central Component of Protein Translocase
Authors: Mori Hiroyuki , Shimokawa Naomi , Satoh Yasunari , Ito Koreaki 
Published: June 2004

ABSTRACT

The SecYEG heterotrimeric membrane protein complex functions as a channel for protein translocation across the
Escherichia coli
cytoplasmic membrane. SecY is the central subunit of the SecYEG complex and contains 10 transmembrane segments (TM1 to TM10). Previous mutation studies suggested that TM3 and TM4 are particularly important for SecY function. To further characterize TM3 and TM4, we introduced a series of cysteine-scanning mutations into these segments. With one exception (an unstable product), all the mutant proteins complemented the cold-sensitive growth defect of the
secY39
mutant. A combination of this
secY
mutation and the
secG
deletion resulted in synthetic lethality, and the TM3 and TM4 SecY cysteine substitution mutations were examined for their ability to complement this lethality. Although they were all positive for complementation, some of the complemented cells exhibited significant retardation of protein export. The substitution-sensitive residues in TM3 can be aligned to one side of the alpha-helix, and those in TM4 revealed a tendency for residues closer to the cytosolic side of the membrane to be more severely affected. Disulfide cross-linking experiments identified a specific contact point for TM3 and SecG TM2 as well as for TM4 and SecG TM1. Thus, although TM3 and TM4 do not contain any single residue that is absolutely required, they include functionally important helix surfaces and specific contact points with SecG. These results are discussed in light of the structural information available for the SecY complex.
Intragenomic Heterogeneity and Intergenomic Recombination among Haloarchaeal rRNA Genes
Authors: Boucher Yan , Douady Christophe J. , Sharma Adrian K. , Kamekura Masahiro , Doolittle W. Ford 
Published: June 2004

ABSTRACT

More than one copy of rRNA operons, which code for both the small-subunit (SSU) and large-subunit (LSU) rRNA, are often found in prokaryotes. It is generally assumed that all rRNA operons within a single cell are almost identical. A notable exception is the extremely halophilic archaeal genus
Haloarcula
, most species of which are known to harbor highly divergent rRNA operons that differ at ∼5% of the nucleotide positions in the SSU gene and at 1 to 2% of the nucleotide positions in the LSU gene. We report that such intragenomic heterogeneity is not unique to
Haloarcula
, as high levels of intragenomic sequence variation have been observed for the SSU genes of two other genera of extreme halophiles,
Halosimplex
and
Natrinema
. To investigate this in detail, the two rRNA operons of
Halosimplex carlsbadense
and the four operons of
Natrinema
sp. strain XA3-1 were cloned and completely sequenced. The SSU and LSU genes of
H. carlsbadense
show the highest levels of intragenomic heterogeneity observed so far in archaea (6.7 and 2.6%). The operons of
Natrinema
sp. strain XA3-1 have additional unusual characteristics, such as identical internal transcribed spacers, while one of four SSU genes is 5% divergent and all LSU genes differ from each other by 0.9 to 1.9%. The heterogeneity among the
Natrinema
sp. strain XA3-1 LSU genes is localized in hot spots, and one of these regions is shown to be the result of a recombination event with a distantly related halophile. This is the first example of interspecies recombination between rRNA genes in archaea, and the recombination occurred over one of the largest phylogenetic distances ever reported for such an event. We suggest that intragenomic heterogeneity of rRNA operons is an ancient and stable trait in several lineages of the
Halobacteriales
. The impact of this phenomenon on the taxonomy of extremely halophilic archaea is discussed.