bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation and storage of white blood cell–reduced split apheresis platelet concentrates for pediatric use
Authors: Van Der Meer Pieter F. , Vrielink Hans , Pietersz Ruby N.I. 
Published: January 2005

BACKGROUND: White blood cell (WBC) reduction and bacterial screening induce unacceptable product loss when platelet (PLT) concentrates (PCs) for pediatric transfusion are prepared from whole blood. The aim was to investigate PCs, WBC reduced and bacterially screened, from single‐donor apheresis procedures, divided in 3 or 4 pediatric units and stored up to 5 days.STUDY DESIGN AND METHODS: PCs were collected with an apheresis machine and WBC reduced by in‐process filtration. The PCs were sampled for bacterial screening and subsequently divided in 70‐mL products. Initially, storage characteristics of split units in 400‐mL polyvinylchloride (PVC) bags with 17 split PCs originating from five apheresis donations were studied. When a 600‐mL container made of the more gas‐permeable polyolefin became available, a paired comparison was performed with 9 split PCs from nine donations and with a higher‐yield PLT collection procedure.RESULTS: Split PCs contained 69 × 109 ± 14 × 109PLTs in 69 ± 1 mL of plasma, and storage in the PVC containers gave a pH value of 6.86 ± 0.10 on Day 6 (mean ± SD, n = 17). When comparing the containers, the PVC bag contained 98 × 109 ± 15 × 109PLTs in 72 ± 4 mL versus 102 × 109 ± 18 × 109PLTs in 74 ± 8 mL for the polyolefin bag (n = 9, not significant). This gave pH values on Day 6 of 6.12 ± 0.50 in the PVC container, whereas pH remained acceptable in the polyolefin container: 6.85 ± 0.10 on Day 6 (p < 0.01).CONCLUSION: PCs for pediatric use from split single‐donor apheresis concentrates, WBC reduced and bacterially screened, can be stored for up to 5 days in a 600‐mL polyolefin container with maintenance of good in vitro storage variables.
Evaluation of the Scansystem method for detection of bacterially contaminated platelets
Authors: Jacobs Michael R. , Bajaksouzian Saralee , Windau Anne , Palavecino Elizabeth L. , Yomtovian Roslyn 
Published: January 2005

BACKGROUND:  Platelet (PLT) bacterial contamination occurs in approximately 1 in 2000 PLT units. The College of American Pathologists recommends and AABB requires procedures to detect PLT bacterial contamination. Although two methods, BacT/ALERT (bioMérieux) and Pall BDS (Pall Corporation), have FDA approval for quality control testing, additional methods are in development. One such method was evaluated, the Scansystem (Hemosystem), which has been developed for use on leukoreduced PLT components between 30 and 72 hours after collection.STUDY DESIGN AND METHODS:  Leukoreduced, single‐donor apheresis PLT units (LR‐SDPs) were inoculated with 10 bacterial species (low and high inocula) associated with PLT contamination. Bacterial detection was compared with the Scansystem and BacT/ALERT. Testing was initiated (10 replicates performed) when LR‐SDPs were experimentally inoculated with bacteria. The Scansystem was evaluated 30 hours later, the shortest manufacturer recommended time after PLT collection.RESULTS:  All replicates were positive with the Scansystem at 30 hours and with the BacT/ALERT, at 9.3 to 24.0 hours after inoculation. The Scansystem detected bacteria in 83 of 200 replicates (42%) at the time of inoculation indicating a potential for earlier application.CONCLUSIONS:  The Scansystem, used to test LR‐SDPs 30 hours after bacterial inoculation, detected all 20 replicates with a sensitivity equal to the BacT/ALERT system. Based on use of Scansystem with LR‐SDPs 30 hours after collection and the BacT/ALERT being inoculated 24 hours after collection and incubated for an additional 24 hours before being determined to be negative, the Scansystem will potentially provide results at an earlier time point (32 hr) than provided by the BacT/ALERT system (48 hr).
Induction of Rapid Detachment in
Shewanella oneidensis
MR-1 Biofilms
Authors: Thormann Kai M. , Saville Renée M. , Shukla Soni , Spormann Alfred M. 
Published: January 2005

ABSTRACT

Active detachment of cells from microbial biofilms is a critical yet poorly understood step in biofilm development. We discovered that detachment of cells from biofilms of
Shewanella oneidensis
MR-1 can be induced by arresting the medium flow in a hydrodynamic biofilm system. Induction of detachment was rapid, and substantial biofilm dispersal started as soon as 5 min after the stop of flow. We developed a confocal laser scanning microscopy-based assay to quantify detachment. The extent of biomass loss was found to be dependent on the time interval of flow stop and on the thickness of the biofilm. Up to 80% of the biomass of 16-h-old biofilms could be induced to detach. High-resolution microscopy studies revealed that detachment was associated with an overall loosening of the biofilm structure and a release of individual cells or small cell clusters. Swimming motility was not required for detachment. Although the loosening of cells from the biofilm structure was observed evenly throughout thin biofilms, the most pronounced detachment in thicker biofilms occurred in regions exposed to the flow of medium, suggesting a metabolic control of detachability. Deconvolution of the factors associated with the stop of medium flow revealed that a sudden decrease in oxygen tension is the predominant trigger for initiating detachment of individual cells. In contrast, carbon limitation did not trigger any substantial detachment, suggesting a physiological link between oxygen sensing or metabolism and detachment. In-frame deletions were introduced into genes encoding the known and putative global transcriptional regulators ArcA, CRP, and EtrA (FNR), which respond to changes in oxygen tension in
S. oneidensis
MR-1. Biofilms of null mutants in
arcA
and
crp
were severely impacted in the stop-of-flow-induced detachment response, suggesting a role for these genes in regulation of detachment. In contrast, an Δ
etrA
mutant displayed a variable detachment phenotype. From this genetic evidence we conclude that detachment is a biologically controlled process and that a rapid change in oxygen concentration is a critical factor in detachment and, consequently, in dispersal of
S. oneidensis
cells from biofilms. Similar mechanisms might also operate in other bacteria.
Characterization of the Pheromone Response of theEnterococcus faecalisConjugative Plasmid pCF10: Complete Sequence and Comparative Analysis of the Transcriptional and Phenotypic Responses of pCF10-Containing Cells to Pheromone Induction
Authors: Hirt Helmut , Manias Dawn A. , Bryan Edward M. , Klein Joanna R. , Marklund Jesper K. , Staddon Jack H. , Paustian Michael L. , Kapur Vivek , Dunny Gary M. 
Published: January 2005

ABSTRACTThe sex pheromone plasmids inEnterococcus faecalisare one of the most efficient conjugative plasmid transfer systems known in bacteria. Plasmid transfer rates can reach or exceed 10−1transconjugants per donor in vivo and under laboratory conditions. We report the completion of the DNA sequence of plasmid pCF10 and the analysis of the transcription profile of plasmid genes, relative to conjugative transfer ability following pheromone induction. These experiments employed a mini-microarray containing all 57 open reading frames of pCF10 and a set of selected chromosomal genes. A clear peak of transcription activity was observed 30 to 60 min after pheromone addition, with transcription subsiding 2 h after pheromone induction. The transcript activity correlated with the ability of donor cells to transfer pCF10 to recipient cells. Remarkably, aggregation substance (Asc10, encoded by theprgBgene) was present on the cell surface for a long period of time after pheromone-induced transcription ofprgBand plasmid transfer ability had ceased. This observation could have relevance for the virulence ofE. faecalis.
Regulation of Virulence by a Two-Component System in Group B
Streptococcus
Authors: Jiang Sheng-Mei , Cieslewicz Michael J. , Kasper Dennis L. , Wessels Michael R. 
Published: January 2005

ABSTRACT

Group B
Streptococcus
(GBS) is frequently carried in the gastrointestinal or genitourinary tract as a commensal organism, yet it has the potential to cause life-threatening infection in newborn infants, pregnant women, and individuals with chronic illness. Regulation of virulence factor expression may affect whether GBS behaves as an asymptomatic colonizer or an invasive pathogen, but little is known about how such factors are controlled in GBS. We now report the characterization of a GBS locus that encodes a two-component regulatory system similar to CsrRS (or CovRS) in
Streptococcus pyogenes
. Inactivation of
csrR
, encoding the putative response regulator, in two unrelated wild-type strains of GBS resulted in a marked increase in production of beta-hemolysin/cytolysin and a striking decrease in production of CAMP factor, an unrelated cytolytic toxin. Quantitative RNA hybridization experiments revealed that these two phenotypes were associated with a marked increase and decrease in expression of the corresponding genes,
cylE
and
cfb
, respectively. The CsrR mutant strains also displayed increased expression of
scpB
encoding C5a peptidase. Similar, but less marked, changes in gene expression were observed in CsrS (putative sensor component) mutants, evidence that CsrR and CsrS constitute a functional two-component system. Experimental infection studies in mice demonstrated reduced virulence of both CsrR and CsrS mutant strains relative to the wild type. Together, these results indicate that CsrRS regulates expression of multiple GBS virulence determinants and is likely to play an important role in GBS pathogenesis.
Genome-Wide Transcriptional Response of Chemostat-CulturedEscherichia colito Zinc
Authors: Lee Lucy J. , Barrett Jason A. , Poole Robert K. 
Published: January 2005

ABSTRACTZinc is an essential trace metal ion for growth, but an excess of Zn is toxic and microorganisms express diverse resistance mechanisms. To understand global bacterial responses to excess Zn, we conducted transcriptome profiling experiments comparingEscherichia coliMG1655 grown under control conditions and cells grown with a toxic, sublethal ZnSO4concentration (0.2 mM). Cultures were grown in a defined medium lacking inorganic phosphate, permitting maximum Zn bioavailability, and in glycerol-limited chemostats at a constant growth rate and pH. Sixty-four genes were significantly up-regulated by Zn stress, including genes known to be involved in Zn tolerance, particularlyzntA,zraP, andhydG. Microarray transcriptome profiling was confirmed by real-time PCR determinations ofcusF(involved in Ag and Cu efflux),ais(an Al-inducible gene),asr(encoding an acid shock-inducible periplasmic protein),cpxP(a periplasmic chaperone gene), andbasR. Five up-regulated genes,basRandbasS[encoding a sensor-regulator implicated inSalmonellain Fe(III) sensing and antibiotic resistance],fliM(flagellar synthesis), andycdMandyibD(both with unknown functions), are important for growth resistance to zinc, since mutants with mutations in these genes exhibited zinc sensitivity in liquid media and on metal gradient plates. Fifty-eight genes were significantly down-regulated by Zn stress; notably, several of these genes were involved in protection against acid stress. Since themdtoperon (encoding a multidrug resistance pump) was also up-regulated, these findings have important implications for understanding not only Zn homeostasis but also how bacterial antibiotic resistance is modulated by metal ions.
NopB, a Type III Secreted Protein of
Rhizobium
sp. Strain NGR234, Is Associated with Pilus-Like Surface Appendages
Authors: Saad Maged M. , Kobayashi Hajime , Marie Corinne , Brown Ian R. , Mansfield John W. , Broughton William J. , Deakin William J. 
Published: January 2005

ABSTRACT

Rhizobium
sp. strain NGR234 possesses a functional type three secretion system (TTSS), through which a number of proteins, called nodulation outer proteins (Nops), are delivered to the outside of the cell. A major constraint to the identification of Nops is their low abundance in the supernatants of NGR234 strains grown in culture. To overcome this limitation, a more sensitive proteomics-based strategy was developed. Secreted proteins from wild-type NGR234 were separated by two-dimensional gel electrophoresis, and the gel was compared to similar gels containing the proteins from a TTSS mutant (NGRΩ
rhcN
). To identify the proteins, spots unique to the NGR234 gels were analyzed by matrix-assisted laser desorption ionization-time of flight mass spectrometry and the data were compared to the sequence of the symbiotic plasmid of NGR234. A nonpolar mutant of one of these proteins was generated called NopB. NopB is required for Nop secretion but inhibits the interaction with
Pachyrhizus tuberosus
and augments nodulation of
Tephrosia vogelii
. Flavonoids and a functional TTSS are required for the formation of some surface appendages on NGR234. In situ immunogold labeling and isolation of these pili showed that they contain NopB.
Specificity and Polymorphism of the PlcR-PapR Quorum-Sensing System in theBacillus cereusGroup
Authors: Slamti Leyla , Lereclus Didier 
Published: January 2005

ABSTRACTThe expression of extracellular virulence factors in various species of theBacillus cereusgroup is controlled by theplcRandpapRgenes, which encode a transcriptional regulator and a cell-cell signaling peptide, respectively. A processed form of PapR, presumably a pentapeptide, specifically interacts with PlcR to facilitate its binding to its DNA targets. This activating mechanism is strain specific, with this specificity being determined by the first residue of the pentapeptide. We carried out in vivo complementation assays and compared the PlcR-PapR sequences of 29 strains from theB. cereusgroup. Our findings suggested that the fifth amino acid of the pentapeptide is also involved in the specificity of activation. We identified four classes of PlcR-PapR pairs, defining four distinct pherotypes in theB. cereusgroup. We used these findings to look at the evolution of the PlcR-PapR quorum-sensing system with regard to the phylogeny of the species forming theB. cereusgroup.
Characterization of Phospholipase Activity of the
Pseudomonas aeruginosa
Type III Cytotoxin, ExoU
Authors: Sato Hiromi , Feix Jimmy B. , Hillard Cecilia J. , Frank Dara W. 
Published: January 2005

ABSTRACT
Recombinant ExoU (rExoU) and yeast extract were used to optimize an in vitro phospholipase assay as a basis for identifying the mechanism for enzyme activation and substrate specificity. Our results support a model in which a eukaryotic protein cofactor or complex facilitates the interaction of rExoU with phospholipid substrates.
Acetic Acid Induces Expression of the
Staphylococcus aureus cidABC
and
lrgAB
Murein Hydrolase Regulator Operons
Authors: Rice Kelly C. , Nelson Jeremy B. , Patton Toni G. , Yang Soo-Jin , Bayles Kenneth W. 
Published: January 2005

ABSTRACT

The
Staphylococcus aureus lrg
and
cid
operons encode homologous proteins that regulate extracellular murein hydrolase activity and penicillin tolerance in a diametrically opposing manner. Although their specific regulatory functions remain unknown, it has been postulated that the functions of CidA and LrgA are analogous to those of bacteriophage holins and antiholins, respectively, and that these proteins serve as molecular control elements of bacterial programmed cell death. Although these studies demonstrated that
cidBC
transcription is abundant in σ
B
-proficient strains,
cidABC
transcription was only minimally expressed under standard growth conditions. In this study, we demonstrate that
cidABC
and
lrgAB
transcription in the clinical isolate UAMS-1 is induced by growth in the presence of 35 mM glucose and that this enhances murein hydrolase activity and decreases tolerance to vancomycin and rifampin. The effect of glucose on murein hydrolase activity was not observed in the
cidA
mutant, indicating that the induction of this activity was dependent on enhanced
cidABC
expression. Furthermore, we demonstrate that the effects of glucose on
cidABC
and
lrgAB
transcription are mediated by the generation of acetic acid produced by the metabolism of this and other carbon sources. These results shed new light on the control of the
S. aureus cidABC
and
lrgAB
genes and demonstrate that these operons, as well as murein hydrolase activity and antibiotic tolerance, are responsive to carbohydrate metabolism.
Expression and Functional Analysis of the Subtilin Immunity Genes
spaIFEG
in the Subtilin-Sensitive Host
Bacillus subtilis
MO1099
Authors: Stein Torsten , Heinzmann Stefan , Düsterhus Stefanie , Borchert Stefan , Entian Karl-Dieter 
Published: January 2005

ABSTRACT

Bacillus subtilis
ATCC 6633 produces the cationic pore-forming lantibiotic subtilin, which preferentially acts on gram-positive microorganisms; self protection of the producer cells is mediated by the four genes
spaIFEG
. To elucidate the mechanism of subtilin autoimmunity, we transferred different combinations of subtilin immunity genes under the control of an inducible promoter into the genome of subtilin-sensitive host strain
B. subtilis
MO1099. Recipient cells acquired subtilin tolerance through expression of either
spaI
or
spaFEG
, which shows that subtilin immunity is based on two independently acting systems. Cells coordinately expressing all four immunity genes acquired the strongest subtilin protection level. Quantitative in vivo peptide release assays demonstrated that SpaFEG diminished the quantity of cell-associated subtilin, suggesting that SpaFEG transports subtilin molecules from the membrane into the extracellular space. Homology and secondary structure analyses define SpaFEG as a prototype of lantibiotic immunity transporters that fall into the ABC-2 subfamily of multidrug resistance proteins. Membrane localization of the lipoprotein SpaI and specific interaction of SpaI with the cognate lantibiotic subtilin suggest a function of SpaI as a subtilin-intercepting protein. This interpretation was supported by hexahistidine-mediated 0-Å cross-linking between hexahistidine-tagged SpaI and subtilin.
Disparate Subcellular Localization Patterns of
Pseudomonas aeruginosa
Type IV Pilus ATPases Involved in Twitching Motility
Authors: Chiang Poney , Habash Marc , Burrows Lori L. 
Published: January 2005

ABSTRACT

The opportunistic pathogen
Pseudomonas aeruginosa
expresses polar type IV pili (TFP), which are responsible for adhesion to various materials and twitching motility on surfaces. Twitching occurs by alternate extension and retraction of TFP, which arise from assembly and disassembly of pilin subunits at the base of the pilus. The ATPase PilB promotes pilin assembly, while the ATPase PilT or PilU or both promote pilin dissociation. Fluorescent fusions to two of the three ATPases (PilT and PilU) were functional, as shown by complementation of the corresponding mutants. PilB and PilT fusions localized to both poles, while PilU fusions localized only to the piliated pole. To identify the portion of the ATPases required for localization, sequential C-terminal deletions of PilT and PilU were generated. The conserved His and Walker B boxes were dispensable for polar localization but were required for twitching motility, showing that localization and function could be uncoupled. Truncated fusions that retained polar localization maintained their distinctive distribution patterns. To dissect the cellular factors involved in establishing polarity, fusion protein localization was monitored with a panel of TFP mutants. The localization of yellow fluorescent protein (YFP)-PilT and YFP-PilU was independent of the subunit PilA, other TFP ATPases, and TFP-associated proteins previously shown to be associated with the membrane or exhibiting polar localization. In contrast, YFP-PilB exhibited diffuse cytoplasmic localization in a
pilC
mutant, suggesting that PilC is required for polar localization of PilB. Finally, localization studies performed with fluorescent ATPase chimeras of PilT and PilU demonstrated that information responsible for the characteristic localization patterns of the ATPases likely resides in their N termini.
Mutants with Temperature-Sensitive Defects in the
Escherichia coli
Mismatch Repair System: Sensitivity to Mispairs Generated In Vivo
Authors: Hong Esther S. , Yeung Annie , Funchain Pauline , Slupska Malgorzata M. , Miller Jeffrey H. 
Published: January 2005

ABSTRACT

We have used direct selections to generate large numbers of mutants of
Escherichia coli
defective in the mismatch repair system and have screened these to identify mutants with temperature-sensitive defects. We detected and sequenced mutations that give rise to temperature-sensitive MutS, MutL, and MutH proteins. One mutation,
mutS60
, results in almost normal levels of spontaneous mutations at 37°C but above this temperature gives rise to higher and higher levels of mutations, reaching the level of null mutations in
mutS
at 43°C. However, at 37°C the MutS60 protein can be much more easily titrated by mispairs than the wild-type MutS, as evidenced by the impaired ability to block homeologous recombination in interspecies crosses and the increased levels of mutations from weak mutator alleles of
mutD
(
dnaQ
),
mutC
, and
ndk
. Strains with
mutS60
can detect mispairs generated during replication that lead to mutation with much greater sensitivity than wild-type strains. The findings with
ndk
, lacking nucleotide diphosphate kinase, are striking. An
ndk mutS60
strain yields four to five times the level of mutations seen in a full knockout of
mutS
. These results pose the question of whether similar altered Msh2 proteins result from presumed polymorphisms detected in tumor lines. The role of allele interactions in human disease susceptibility is discussed.
Identification and Characterization of Genes Involved in the Downstream Degradation Pathway of γ-Hexachlorocyclohexane in
Sphingomonas paucimobilis
UT26
Authors: Endo Ryo , Kamakura Mayuko , Miyauchi Keisuke , Fukuda Masao , Ohtsubo Yoshiyuki , Tsuda Masataka , Nagata Yuji 
Published: January 2005

ABSTRACT

Sphingomonas paucimobilis
UT26 utilizes γ-hexachlorocyclohexane (γ-HCH) as a sole source of carbon and energy. In our previous study, we cloned and characterized genes that are involved in the conversion of γ-HCH to maleylacetate (MA) via chlorohydroquinone (CHQ) in UT26. In this study, we identified and characterized an MA reductase gene, designated
linF
, that is essential for the utilization of γ-HCH in UT26. A gene named
linEb
, whose deduced product showed significant identity to LinE (53%), was located close to
linF
. LinE is a novel type of ring cleavage dioxygenase that catalyzes the conversion of CHQ to MA. LinEb expressed in
Escherichia coli
transformed CHQ and 2,6-dichlorohydroquinone to MA and 2-chloromaleylacetate, respectively. Our previous and present results indicate that UT26 (i) has two gene clusters for degradation of chlorinated aromatic compounds via hydroquinone-type intermediates and (ii) uses at least parts of both clusters for γ-HCH utilization.