bluuebunny/crossref_metadata_2025_split huggingface dataset:
Genome-Wide Transcriptional Profiling of the Steady-State Response of
Pseudomonas aeruginosa
to Hydrogen Peroxide
Authors: Salunkhe Prabhakar , Töpfer Tanja , Buer Jan , Tümmler Burkhard 
Published: April 2005

ABSTRACT

The steady-state response of
Pseudomonas aeruginosa
to the oxidative-stress-generating agent hydrogen peroxide was analyzed by PAO1 transcriptome profiling. In total, 694, 411, and 237 genes were upregulated and 668, 576, and 468 genes were downregulated in
P. aeruginosa
strains TB, 892, and PAO1, respectively. The expression profiles of the two variants of the TB clone were significantly more related to each other than the expression profile of either strain was to that of PAO1. Exposure to H
2
O
2
activated by more than 10-fold the expression of the
cyoABCD
operon, which is key for aerobic respiration, and of oxidative-stress response elements such as the catalase KatB, the alkyl hydroperoxide reductase AhpF, and the thioredoxin reductase 2 operon. Genes for iron and sulfur homeostasis were upregulated. Most enzymes necessary for the conversion of amino acids into the citric acid cycle were globally downregulated at the transcriptional level. Nitrate respiration and arginine fermentation were shut off in the clone TB strains and attenuated in the PAO strain. The transcriptional profiles indicate that the two clone TB strains are more proficient in coping with H
2
O
2
-mediated oxidative stress than the reference strain PAO. According to this data, we recommend study of the transcriptome of strain PAO1 in parallel with those of at least two strains of another clone in order to differentiate common responses from clone- and strain-specific responses and to minimize overinterpretations of microarray data.
Expression of thebmpBGene ofBorrelia burgdorferiIs Modulated by Two Distinct Transcription Termination Events
Authors: Ramamoorthy Ramesh , McClain Natalie A. , Gautam Aarti , Scholl-Meeker Dorothy 
Published: April 2005

ABSTRACTbmpgene family 36 ofBorrelia burgdorferi, the agent of Lyme disease, comprises four paralogs:bmpA,bmpB,bmpC, andbmpD. ThebmpAandbmpBgenes constitute an operon. All four genes have been found to be transcribed in cultured spirochetes. Expression from thebmpABoperon results in three distinct transcripts of 1.1, 1.6, and 2.4 kb, and the relative expression ofbmpAmRNA is three- to fourfold greater than that ofbmpBmRNA. However, thus far only expression of the BmpA protein has been demonstrated. Therefore, in this study we characterized the origins of the three transcripts and compared the relative expression of the BmpA and BmpB proteins. Northern blotting revealed that the three distinct transcripts originated from a single promoter located upstream ofbmpAbut terminated either 3′ to thebmpA(1.1-kb RNA) orbmpB(2.4-kb RNA) gene or, most unusually, within thebmpBgene (1.6-kb RNA). Termination within thebmpBgene was associated with a functional Rho-independent transcription terminator. At the protein level, we also observed a 4.3-fold greater abundance of BmpA compared to that of BmpB. These studies identify a transcription termination mechanism inB. burgdorferiresulting in the disparate expression of the two genes of thebmpABoperon.
The Metalloprotease ofListeria monocytogenesControls Cell Wall Translocation of the Broad-Range Phospholipase C
Authors: Yeung P. S. Marie , Zagorski Nicholas , Marquis Hélène 
Published: April 2005

ABSTRACTListeria monocytogenesis a gram-positive bacterial pathogen that multiplies in the cytosol of host cells and spreads directly from cell to cell. During cell-to-cell spread, bacteria become temporarily confined to secondary vacuoles. The broad-range phospholipase C (PC-PLC) ofL. monocytogenescontributes to bacterial escape from secondary vacuoles. PC-PLC requires cleavage of an N-terminal propeptide for activation, and Mpl, a metalloprotease ofListeria, is involved in the proteolytic activation of PC-PLC. Previously, we showed that cell wall translocation of PC-PLC is inefficient, resulting in accumulation of PC-PLC at the membrane-cell wall interface. In infected cells, rapid cell wall translocation of PC-PLC is triggered by a decrease in pH and correlates with cleavage of the propeptide in an Mpl-dependent manner. To address the role of the propeptide and of Mpl in cell wall translocation of PC-PLC, we generated a cleavage site mutant and a propeptide deletion mutant. The intracellular behavior of these mutants was assessed in pulse-chase experiments. We observed efficient translocation of the proform of the PC-PLC cleavage site mutant in a manner that was pH sensitive and Mpl dependent. However, the propeptide deletion mutant was efficiently translocated into host cells independent of Mpl and pH. Overall, these results suggest that Mpl regulates PC-PLC translocation across the bacterial cell wall in a manner that is dependent on the presence of the propeptide but independent of propeptide cleavage. In addition, similarly to Mpl-mediated cleavage of PC-PLC propeptide, Mpl-mediated translocation of PC-PLC across the bacterial cell wall is pH sensitive.
Identification of Cyclic AMP-Regulated Genes in
Mycobacterium tuberculosis
Complex Bacteria under Low-Oxygen Conditions
Authors: Gazdik Michaela A. , McDonough Kathleen A. 
Published: April 2005

ABSTRACT

Mycobacterium tuberculosis
is the etiological agent of tuberculosis (TB), which kills approximately 2 million people a year despite current treatment options. A greater understanding of the biology of this bacterium is needed to better combat TB disease. The
M. tuberculosis
genome encodes as many as 15 adenylate cyclases, suggesting that cyclic AMP (cAMP) has an important, yet overlooked, role in mycobacteria. This study examined the effect of exogenous cAMP on protein expression in
Mycobacterium bovis
BCG grown under hypoxic versus ambient conditions. Both shaking and shallow standing cultures were examined for each atmospheric condition. Different cAMP-dependent changes in protein expression were observed in each condition by two-dimensional gel electrophoresis. Shaking low-oxygen cultures produced the most changes (12), while standing ambient conditions showed the fewest (2). Five upregulated proteins, Rv1265, Rv2971, GroEL2, PE_PGRS6a, and malate dehydrogenase, were identified from BCG by mass spectrometry and were shown to also be regulated by cAMP at the mRNA level in both
M. tuberculosis
H37Rv and BCG. To our knowledge, these data provide the first direct evidence for cAMP-mediated gene regulation in TB complex mycobacteria.
Completion of the Genome Sequence of
Brucella abortus
and Comparison to the Highly Similar Genomes of
Brucella melitensis
and
Brucella suis
Authors: Halling Shirley M. , Peterson-Burch Brooke D. , Bricker Betsy J. , Zuerner Richard L. , Qing Zhang , Li Ling-Ling , Kapur Vivek , Alt David P. , Olsen Steven C. 
Published: April 2005

ABSTRACT

Brucellosis
is a worldwide disease of humans and livestock that is caused by a
number of very closely related classical
Brucella
species in
the alpha-2 subdivision of the Proteobacteria. We report the complete
genome sequence of
Brucella abortus
field isolate 9-941 and
compare it to those of
Brucella suis
1330 and
Brucella
melitensis
16 M. The genomes of these
Brucella
species
are strikingly similar, with nearly identical genetic content and gene
organization. However, a number of insertion-deletion events and
several polymorphic regions encoding putative outer membrane proteins
were identified among the genomes. Several fragments previously
identified as unique to either
B. suis
or
B.
melitensis
were present in the
B. abortus
genome. Even
though several fragments were shared between only
B. abortus
and
B. suis
,
B. abortus
shared more fragments and had
fewer nucleotide polymorphisms with
B. melitensis
than
B.
suis
. The complete genomic sequence of
B. abortus
provides an important resource for further investigations into
determinants of the pathogenicity and virulence phenotypes of these
bacteria.
Surprising Dependence on Postsegregational Killing of Host Cells for Maintenance of the Large Virulence Plasmid of
Shigella flexneri
Authors: Sayeed Sameera , Brendler Therese , Davis Michael , Reaves Lucretia , Austin Stuart 
Published: April 2005

ABSTRACT

Low-copy-number plasmids all encode multiple systems to ensure their propagation, including replication, partition (active segregation), and postsegregational killing (PSK) systems. PSK systems kill those rare cells that lose the plasmid due to replication or segregation errors. PSK systems should not be used as the principle means of maintaining the plasmid. The metabolic cost of killing the many cured cells that would arise from random plasmid segregation is far too high. Here we describe an interesting exception to this rule. Maintenance of the large virulence plasmid of
Shigella flexneri
is highly dependent on one of its PSK systems,
mvp
, at 37°C, the temperature experienced during pathogenesis. At 37°C, the plasmid is very unstable and mvp efficiently kills the resulting cured bacterial cells. This imposes a major growth disadvantage on the virulent bacterial population. The systems that normally ensure accurate plasmid replication and segregation are attenuated or overridden at 37°C. At 30°C, a temperature encountered by
Shigella
in the outside environment, the maintenance systems function normally and the plasmid is no longer dependent on
mvp
. We discuss why the virulent pathogen tolerates this self-destructive method of propagation at the temperature of infection.
Enhanced Synthesis of Internalin A inaroMutants ofListeria monocytogenesIndicates Posttranscriptional Control of theinlABmRNA
Authors: Stritzker Jochen , Schoen Christoph , Goebel Werner 
Published: April 2005

ABSTRACTListeria monocytogenesmutants with deletions inaroA,aroB, oraroEexhibited strong posttranscriptional upregulation of internalin A (InlA) and InlB synthesis, which resulted in a more-than-10-fold increase in InlA-mediated internalization by epithelial Caco-2 cells and a 4-fold increase in InlB-mediated internalization by microvascular endothelial cells (human brain microvascular endothelial cells) compared to the wild-type strain. The increase in InlA and InlB production was not due to enhanced PrfA- and/or sigma factor B (SigB)-dependentinlABtranscription but was caused by enhanced translation of theinlABtranscripts in thearomutants. AllinlA(B) transcripts had a 396-nucleotide upstream 5′ untranslated region (UTR). Different deletions introduced into this UTR led to significant reductions in InlA and InlB synthesis; enhanced translation of all of the truncated transcripts in thearomutants was, however, still observed. Thus, translation of theinlABtranscripts was subject to two modes of posttranscriptional control, one mediated by the UTR structure and the other mediated by thearomutation. The latter mode of control seemed to be related to the predominantly anaerobic metabolism of thearomutants.
Characterization of Type 2 Quorum Sensing in
Klebsiella pneumoniae
and Relationship with Biofilm Formation
Authors: Balestrino Damien , Haagensen Janus A. J. , Rich Chantal , Forestier Christiane 
Published: April 2005

ABSTRACT

Quorum sensing is a process by which bacteria communicate by using secreted chemical signaling molecules called autoinducers. Many bacterial species modulate the expression of a wide variety of physiological functions in response to changes in population density by this mechanism. In this study, the opportunistic pathogen
Klebsiella pneumoniae
was observed to secrete type 2 signaling molecules. A homologue of
luxS
, the gene required for AI-2 synthesis in
Vibrio harveyi
, was isolated from the
K. pneumoniae
genome. A
V. harveyi
bioassay showed the
luxS
functionality in
K. pneumoniae
and its ability to complement the
luxS
-negative phenotype of
Escherichia coli
DH5α. Autoinducer activity was detected in the supernatant, and maximum expression of specific messengers detected by quantitative reverse transcription-PCR analysis occurred during the late exponential phase. The highest levels of AI-2 were observed in minimal medium supplemented with glycerol. To determine the potential role of
luxS
in colonization processes, a
K. pneumoniae luxS
isogenic mutant was constructed and tested for its capacity to form biofilms in vitro on an abiotic surface and to colonize the intestinal tract in a murine model. No difference was observed in the level of intestinal colonization between the wild-type strain and the
luxS
mutant. Microscopic analysis of biofilm structures revealed that the
luxS
mutant was able to form a mature biofilm but with reduced capacities in the development of microcolonies, mostly in the early steps of biofilm formation. These data suggest that a LuxS-dependent signal plays a role in the early stages of biofilm formation by
K. pneumoniae
.
Functional Reassembly of the
Escherichia coli
Maltose Transporter following Purification of a MalF-MalG Subassembly
Authors: Sharma Susan , Davis Johnny A. , Ayvaz Tulin , Traxler Beth , Davidson Amy L. 
Published: April 2005

ABSTRACT

Taking advantage of a chaperone-like function of MalK, a stable complex of MalF-MalG could be solubilized from the
Escherichia coli
membrane and purified in high yield in the absence of MalK. This MalF-MalG complex was competent for efficient reassembly of a functional MalFGK
2
maltose transporter complex both in detergent solution and in proteoliposomes.
Identification of
rcnA
(
yohM
), a Nickel and Cobalt Resistance Gene in
Escherichia coli
Authors: Rodrigue Agnès , Effantin Géraldine , Mandrand-Berthelot Marie-Andrée 
Published: April 2005

ABSTRACT

We report here on the isolation and primary characterization of the
yohM
gene of
Escherichia coli
. We show that
yohM
encodes a membrane-bound polypeptide conferring increased nickel and cobalt resistance in
E. coli. yohM
was specifically induced by nickel or cobalt but not by cadmium, zinc, or copper. Mutation of
yohM
increased the accumulation of nickel inside the cell, whereas cells harboring
yohM
in multicopy displayed reduced intracellular nickel content. Our data support the hypothesis that YohM is the first described efflux system for nickel and cobalt in
E. coli
. We propose
rcnA
(resistance to cobalt and nickel) as the new denomination of
yohM
.
Comparison of injury case fatality rates in the United States and New Zealand
Authors: Spicer R , Miller T , Langley J , Stephenson S 
Published: April 2005

Objective:To compare injury case fatality rates in the United States (US) with New Zealand (NZ) to guide future information collection, research, and evaluation.Design:Using NZ (1992–96) and US (1996–98) mortality censuses, NZ national 1992–96 hospital discharge censuses, and US 1996–98 National Hospital Discharge Survey data, the authors compared case fatality rates by mechanism and intent of injury and age group. The analysis was restricted to severe injuries (AIS⩾3).Subjects:NZ (1992–96) and US (1996–98) populations.Main outcome measures:Ratio of case fatality rates in NZ versus the US (RCFR(NZ:US)).Results:Overall, among cases meeting the study criteria, unintentional injuries were 1.57 times more likely fatal in NZ and intentional assault injuries were 1.14 times more likely to be fatal in the US. Firearms were involved in 50% of US assaults versus 8% of NZ assaults. By mechanism, cutting/piercing injuries were 1.86, firearm injuries were 1.41, and motor vehicle injuries were 1.44 times more to be likely fatal in NZ. Natural/environmental injuries (RCFRNZ:US = 0.57), unintentional poisonings (RCFRNZ:US = 0.26), and unintentional suffocations (RCFRNZ:US = 0.67) were significantly more likely to be fatal in the US.Conclusions:Possible reasons for the observed results include: differences in geography and proportion of population in rural areas, trauma system differences, road design and vehicle types, seat belt use, larger role of firearms in US assaults, coding practices, policies, and environmental factors. Disparities evoke hypotheses to test in future research that will guide priority setting and intervention.
Gender differences for non-fatal unintentional fall related injuries among older adults
Authors: Stevens J A , Sogolow E D 
Published: April 2005

Objectives:To quantify gender differences for non-fatal unintentional fall related injuries among US adults age 65 years and older treated in hospital emergency departments (EDs).Methods:The authors analyzed data from a nationally representative sample of ED visits for January 2001 through December 2001, available through the National Electronic Injury Surveillance System All Injury Program (NEISS-AIP). For each initial ED visit, coders record one principal diagnosis (usually the most severe) and one primary part of the body affected.Results:Based on 22 560 cases, an estimated 1.64 million older adults were treated in EDs for unintentional fall injuries. Of these, approximately 1.16 million, or 70.5%, were women. Fractures, contusions/abrasions, and lacerations accounted for more than three quarters of all injuries. Rates for injury diagnoses were generally higher among women, most notably for fractures which were 2.2 times higher than for men. For all parts of the body, women’s injury rates exceeded those of men. Rate ratios were greatest for injuries of the leg/foot (2.3), arm/hand (2.0), and lower trunk (2.0). The hospitalization rate for women was 1.8 times that for men.Conclusions:Among older adults, non-fatal fall related injuries disproportionately affected women. Much is known about effective fall prevention strategies. We need to refine, promote, and implement these interventions. Additional research is needed to tailor interventions for different populations and to determine gender differences in the underlying causes and/or circumstances of falls. This information is vital for developing and implementing targeted fall prevention strategies.
Winning, losing, and violence
Authors: Sivarajasingam V , Moore S , Shepherd J P 
Published: April 2005

Background:Although international sports events attract huge interest, and results can be a barometer of popular national standing, their impact on violent behaviour has not been investigated.Methods:Associations between assault related emergency department (ED) attendances and international sporting events (home and away rugby and soccer matches) in a European capital city (Cardiff) served by one ED, between 1 May 1995 and 30 April 2002 were investigated. The frequency of assault related ED attendances were studied relative to whether the national team won or lost, controlling for potential covariates: match attendance, match location (home/away), results (win/lose), net scores, and day of match (weekend/weekday). Multiple linear regression was used to identify significant associations with ED assault related attendances.Results:Matches which the Wales team won (p = 0.03), match attendance (p<0.001), and weekend matches (p<0.001) were positively associated with ED assault related injury attendances. Assault frequency measured in this way was no different for home and away matches.Conclusions:Assault injury resulting in ED treatment was more frequent when national teams won than when they lost. Sport type made no difference. Violence prevention efforts should be increased on international match days, when the national team is expected to win, when match attendance is large, and for away as well as home matches.
A NOTE ON REPEATED GAMES WITH VANISHING ACTIONS
Authors: JOOSTEN REINOUD 
Published: April 2005

A two-person general-sum repeated game with vanishing actions is an infinitely repeated game where the players face the following restrictions. Each action must be used by player k ∈ {1,2} at least once in every rk ∈ ℕ consecutive stages, otherwise the action vanishes for the remaining play. We assume that the players wish to maximize their limiting average rewards over the entire time-horizon. A strategy-pair is jointly convergent if for each action pair a number exists to which the relative frequency with which this action pair is chosen, converges with probability one. A pair of feasible rewards is called individually rational if each player receives at least the threat-point reward, i.e., the amount which he can guarantee himself regardless of what the opponent does given r1, r2 and the actions available in the long run. In a repeated game with vanishing actions, there may exist multiple threat points which are endogenous to the play. We prove that all individually-rational jointly-convergent pure-strategy rewards can be supported by an equilibrium. Furthermore, each convex combination of individually-rational jointly-convergent pure-strategy rewards, can be supported by an equilibrium for m × n-games provided r1 > m ≥ 2, r2 > n ≥ 2.
The natural product honokiol induces caspase-dependent apoptosis in B-cell chronic lymphocytic leukemia (B-CLL) cells
Authors: Battle Traci E. , Arbiser Jack , Frank David A. 
Published: April 2005

Abstract
B-cell chronic lymphocytic leukemia (B-CLL) remains an incurable disease that requires innovative new approaches to improve therapeutic outcome. Honokiol is a natural product known to possess potent antineoplastic and antiangiogenic properties. We examined whether honokiol can overcome apoptotic resistance in primary tumor cells derived from B-CLL patients. Honokiol induced caspase-dependent cell death in all of the B-CLL cells examined and was more toxic toward B-CLL cells than to normal mononuclear cells, suggesting greater susceptibility of the malignant cells. Honokiol-induced apoptosis was characterized by the activation of caspase-3, -8, and -9 and cleavage of poly(adenosine diphosphate-ribose) polymerase (PARP). Exposure of B-CLL cells to honokiol resulted in up-regulation of Bcl2-associated protein (Bax) and down-regulation of the expression of the key survival protein myeloid-cell leukemia sequence 1 (Mcl-1), which is associated with response to treatment in B-CLL patients. In addition, B-CLL cells pretreated with interleukin-4 (IL-4), a cytokine known to support B-CLL survival, underwent apoptosis when subsequently incubated with honokiol, indicating that honokiol could also overcome the prosurvival effects of IL-4. Furthermore, honokiol enhanced cytotoxicity induced by fludarabine, cladribine, or chlorambucil. These data indicate that honokiol is a potent inducer of apoptosis in B-CLL cells and should be examined for further clinical application either as a single agent or in combination with other anticancer agents. (Blood. 2005;106:690-697)
The FA/BRCA pathway is involved in melphalan-induced DNA interstrand cross-link repair and accounts for melphalan resistance in multiple myeloma cells
Authors: Chen Qing , Van der Sluis Pieter C. , Boulware David , Hazlehurst Lori A. , Dalton William S. 
Published: April 2005

Abstract
Melphalan, a DNA cross-linker, is one of the most widely used and effective drugs in the treatment of multiple myeloma (MM). In this report, we demonstrate that enhanced interstrand cross-link (ICL) repair via the Fanconi anemia (FA)/BRCA pathway contributes to acquired drug resistance in melphalan-resistant myeloma cell lines, and disruption of this pathway reverses drug resistance. Using the alkaline comet assay (single-cell gel electrophoresis), we observed that melphalan-resistant cells have reduced ICL formation and enhanced ICL repair compared with melphalan-sensitive cells. Cell-cycle studies demonstrated that enhanced ICL repair released cells from melphalan-induced cell-cycle delay. Using siRNA to knock down FANCF in 8226/LR5 and U266/LR6 drug-resistant cells demonstrated a direct relationship between ICL repair capacity and drug sensitivity. Overexpression of FANCF in 8226/S and U266/S drug-sensitive cells partially reproduced the drug-resistant phenotype. These data show that enhanced DNA repair via the Fanconi anemia/BRCA pathway is involved in acquired melphalan resistance. Our findings provide for a new target to enhance response to DNA cross-linking agents in cancer treatment. (Blood. 2005;106:698-705)