bluuebunny/crossref_metadata_2025_split huggingface dataset:
Crystal Structure of the Response Regulator 02 Receiver Domain, the Essential YycF Two-Component System ofStreptococcus pneumoniaein both Complexed and Native States
Authors: Bent Colin J. , Isaacs Neil W. , Mitchell Timothy J. , Riboldi-Tunnicliffe Alan 
Published: April 2004

ABSTRACTA variety of bacterial cellular responses to environmental signals are mediated by two-component signal transduction systems comprising a membrane-associated histidine protein kinase and a cytoplasmic response regulator (RR), which interpret specific stimuli and produce a measured physiological response. In RR activation, transient phosphorylation of a highly conserved aspartic acid residue drives the conformation changes needed for full activation of the protein. Sequence homology reveals that RR02 fromStreptococcus pneumoniaebelongs to the OmpR subfamily of RRs. The structures of the receiver domains from four members of this family, DrrB and DrrD fromThermotoga maritima, PhoB fromEscherichia coli, and PhoP fromBacillus subtilis, have been elucidated. These domains are globally very similar in that they are composed of a doubly wound α5β5; however, they differ remarkably in the fine detail of the β4-α4 and α4 regions. The structures presented here reveal a further difference of the geometry in this region. RR02 is has been shown to be the essential RR in the gram-positive bacteriumS. pneumoniaeR. Lange, C. Wagner, A. de Saizieu, N. Flint, J. Molnos, M. Stieger, P. Caspers, M. Kamber, W. Keck, and K. E. Amrein, Gene 237:223-234, 1999; J. P. Throup, K. K. Koretke, A. P. Bryant, K. A. Ingraham, A. F. Chalker, Y. Ge, A. Marra, N. G. Wallis, J. R. Brown, D. J. Holmes, M. Rosenberg, and M. K. Burnham, Mol. Microbiol. 35:566-576, 2000). RR02 functions as part of a phosphotransfer system that ultimately controls the levels of competence within the bacteria. Here we report the native structure of the receiver domain of RR02 from serotype 4S. pneumoniae(as well as acetate- and phosphate-bound forms) at different pH levels. Two native structures at 2.3 Å, phased by single-wavelength anomalous diffraction (xenon SAD), and 1.85 Å and a third structure at pH 5.9 revealed the presence of a phosphate ion outside the active site. The fourth structure revealed the presence of an acetate molecule in the active site.
Biofilm Formation in
Pseudomonas aeruginosa
: Fimbrial
cup
Gene Clusters Are Controlled by the Transcriptional Regulator MvaT
Authors: Vallet Isabelle , Diggle Stephen P. , Stacey Rachael E. , Cámara Miguel , Ventre Isabelle , Lory Stephen , Lazdunski Andrée , Williams Paul , Filloux Alain 
Published: April 2004

ABSTRACT

Pseudomonas aeruginosa
is an opportunistic bacterial pathogen which poses a major threat to long-term-hospitalized patients and individuals with cystic fibrosis. The capacity of
P. aeruginosa
to form biofilms is an important requirement for chronic colonization of human tissues and for persistence in implanted medical devices. Various stages of biofilm formation by this organism are mediated by extracellular appendages, such as type IV pili and flagella. Recently, we identified three
P. aeruginosa
gene clusters that were termed
cup
(chaperone-usher pathway) based on their sequence relatedness to the chaperone-usher fimbrial assembly pathway in other bacteria. The
cupA
gene cluster, but not the
cupB
or
cupC
cluster, is required for biofilm formation on abiotic surfaces. In this study, we identified a gene (
mvaT
) encoding a negative regulator of
cupA
expression. Such regulatory control was confirmed by several approaches, including
lacZ
transcriptional fusions, Northern blotting, and transcriptional profiling using DNA microarrays. MvaT also represses the expression of the
cupB
and
cupC
genes, although the extent of the regulatory effect is not as pronounced as with
cupA
. Consistent with this finding,
mvaT
mutants exhibit enhanced biofilm formation. Although the
P. aeruginosa
genome contains a highly homologous gene,
mvaU
, the repression of
cupA
genes is MvaT specific. Thus, MvaT appears to be an important regulatory component within a complex network that controls biofilm formation and maturation in
P. aeruginosa
.
Polymerases Leave Fingerprints: Analysis of the Mutational Spectrum in
Escherichia coli rpoB
To Assess the Role of Polymerase IV in Spontaneous Mutation
Authors: Wolff Erika , Kim Mandy , Hu Kaibin , Yang Hanjing , Miller Jeffrey H. 
Published: April 2004

ABSTRACT

We compared the distribution of mutations in
rpoB
that lead to rifampin resistance in strains with differing levels of polymerase IV (Pol IV), including strains with deletions of the Pol IV-encoding
dinB
gene, strains with a chromosomal copy of
dinB
, strains with the F′128 plasmid, and strains with plasmid amplification of either the
dinB
operon (
dinB-yafNOP
) or the
dinB
gene alone. This analysis identifies several hot spots specific to Pol IV which are virtually absent from the normal spontaneous spectrum, indicating that Pol IV does not contribute significantly to mutations occurring during exponential growth in liquid culture.
Correlation between Osmolarity and Luminescence of Symbiotic
Vibrio fischeri
Strain ES114
Authors: Stabb Eric V. , Butler Melissa S. , Adin Dawn M. 
Published: April 2004

ABSTRACT

Vibrio fischeri
isolates from
Euprymna scolopes
are dim in culture but bright in the host. We found the luminescence of
V. fischeri
to be correlated with external osmolarity both in culture and in this symbiosis. Luminescence enhancement by osmolarity was independent of the
lux
promoter and unaffected by autoinducers or the level of
lux
expression, but the addition of an aldehyde substrate for luciferase raised the luminescence of cells grown at high and low osmolarities to the same high level.
V. fischeri
culture media have lower osmolarities than are typical in seawater or in cephalopods, partially accounting for the bacterium's low light output in culture.
Aircraft noise around a large international airport and its impact on general health and medication use
Authors: Franssen E A M , van Wiechen C M A G , Nagelkerke N J D , Lebret E 
Published: April 2004

Aims:To assess the prevalence of general health status, use of sleep medication, and use of medication for cardiovascular diseases, and to study their relation to aircraft noise exposure.Methods:These health indicators were measured by a cross-sectional survey among 11 812 respondents living within a radius of 25 km around Schiphol airport (Amsterdam).Results:Adjusted odds ratios ranged from 1.02 to 2.34 per 10 dB(A) increase in Lden. The associations were statistically significant for all indicators, except for use of prescribed sleep medication or sedatives and frequent use of this medication. None of the health indicators were associated with aircraft noise exposure during the night, but use of non-prescribed sleep medication or sedatives was associated with aircraft noise exposure during the late evening (OR = 1.72). Vitality related health complaints such as tiredness and headache were associated with aircraft noise, whereas most other physical complaints were not. Odds ratios for the vitality related complaints ranged from 1.16 to 1.47 per 10 dB(A) increase in Lden. A small fraction of the prevalence of poor self rated health (0.13), medication for cardiovascular diseases or increased blood pressure (0.08), and sleep medication or sedatives (0.22) could be attributed to aircraft noise. Although the attributable fraction was highest in the governmentally noise regulated area, aircraft noise had more impact in the non-regulated area, due to the larger population.Conclusions:Results suggest associations between community exposure to aircraft noise and the health indicators poor general health status, use of sleep medication, and use of medication for cardiovascular diseases.
Quantifying the advantages and disadvantages of pre-placement genetic screening
Authors: Palmer K T , Poole J , Rawbone R G , Coggon D 
Published: April 2004

Background:Tests of genotype may enable workers at unusual risk of future ill-health to be identified. Using them to select for employment, however, entails gains and losses to employers and employees. Ensuring a fair balance between the rights and obligations of each group requires a value judgement, but the advantages and disadvantages to interested parties must first be quantified in a meaningful way.Method and Results:The purposes of pre-employment screening are reviewed, and several simple measures relevant to the separate interests of employers and job applicants proposed—number screened to prevent a single adverse outcome; number excluded to prevent a case; expected incidence of the adverse outcome in those excluded; and preventable fraction. The derivation of these measures is illustrated, and the factors that influence them (the prevalence of the prognostic trait, the relative risk that it carries for an adverse outcome, and the overall incidence of disease) are related algebraically and graphically, to aid judgement on the utility of screening under different circumstances.Conclusions:In sensitive areas such as genetic testing the onus should be on the employer to justify plans for pre-placement screening. Several quantitative measures can be used to inform the ethical and economic debate about screening and to evaluate alternative strategies for prevention.
Increased inflammation and altered macrophage chemotactic responses caused by two ultrafine particle types
Authors: Renwick L C , Brown D , Clouter A , Donaldson K 
Published: April 2004

Background:Ultrafine particles have been hypothesised to be an important contributing factor in the toxicity and adverse health effects of particulate air pollution (PM10) and nanoparticles are used increasingly in industrial processes.Aims:To compare the ability of ultrafine and fine particles of titanium dioxide and carbon black to induce inflammation, cause epithelial injury, and affect the alveolar macrophage clearance functions of phagocytosis and chemotaxis in vivo.Methods:Rats were instilled with fine and ultrafine carbon black and titanium dioxide. Inflammation was quantified by bronchoalveolar lavage; the ability of the macrophages to phagoytose indictor fluorescent beads and to migrate towards aC5a were determined.Results:Ultrafine particles induced more PMN recruitment, epithelial damage, and cytotoxicity than their fine counterparts, exposed at equal mass. Both ultrafine and fine particles significantly impaired the phagocytic ability of alveolar macrophages. Only ultrafine particle treatment significantly enhanced the sensitivity of alveolar macrophages to chemotact towards C5a.Conclusions:Ultrafine particles of two very different materials induced inflammation and epithelial damage to a greater extent than their fine counterparts. In general, the effect of ultrafine carbon black was greater than ultrafine titanium dioxide, suggesting that there are differences in the likely harmfulness of different types of ultrafine particle. Epithelial injury and toxicity were associated with the development of inflammation after exposure to ultrafines. Increased sensitivity to a C5a chemotactic gradient could make the ultrafine exposed macrophages more likely to be retained in the lungs, so allowing dose to accumulate.
Work factors as predictors of intense or disabling low back pain; a prospective study of nurses’ aides
Authors: Eriksen W , Bruusgaard D , Knardahl S 
Published: April 2004

Aims:To identify the work factors that predict intense low back pain (LBP) and LBP related sick leaves in nurses’ aides.Methods:The sample comprised 4266 randomly selected Norwegian nurses’ aides, not bothered or only a little bothered by LBP during the previous three months, and not on sick leave when completing a mailed questionnaire in 1999. Of these, 3808 (89.3%) completed a second questionnaire 3 months later and 3651 (85.6%) completed a third questionnaire 15 months later. Intensity of low back symptoms and certified sick leaves attributed to LBP during the observation period were assessed by self reports at the follow ups.Results:After adjustments for LBP during the three months prior to baseline, baseline health complaints, demographic and familial factors, and a series of physical, psychological, and social work factors, logistic regression analyses revealed the following associations: intense low back symptoms were predicted by frequent positioning of patients in bed, perceived lack of support from immediate superior, and perceived lack of pleasant and relaxing culture in the work unit. LBP related sick leaves were predicted by frequent handling of heavy objects, medium level of work demands, perceived lack of supportive and encouraging culture in the work unit, working night shifts, and working in a nursing home. Long term LBP related sick leaves were associated with changes of work or work tasks during the observation period that resulted in a perceived reduction of support and encouragement at work.Conclusions:Not only frequent mechanical exposures, but also organisational, psychological, and social work factors, such as night shift work, perceived lack of support from superior, and perceived lack of a pleasant and relaxing or supporting and encouraging culture in the work unit, are associated with an increased risk of intense low back symptoms and LBP related sick leaves in nurses’ aides.
Prevalence of chronic fatigue syndrome-like caseness in the working population: results from the Maastricht cohort study: Table 1
Authors: Huibers M J H , Kant IJ , Swaen G M H , Kasl S V 
Published: April 2004

Aim:To determine the prevalence of chronic fatigue syndrome (CFS)-like caseness in the working population.Methods:Using data from the prospective Maastricht Cohort Study on Fatigue at Work, the prevalence and incidence of CFS-like cases (employees meeting research criteria for CFS) were determined among 5499 employees who responded to the follow up assessment 3 years and 8 months after baseline.Results:Of the 5499 employees, 199 (3.6%) were identified as CFS-like cases. By deleting possible CFS-like cases at baseline, the annual incidence of CFS-like caseness was estimated to be 85 per 10 000. Twenty employees (0.36%) reported having been diagnosed with CFS by a physician.Conclusions:The prevalence of CFS-like cases (3.6%) was considerably higher than the prevalence of CFS reported in previous studies (0.006–3%). These findings suggest that the CFS-like caseness may be underdetected in the working population and perhaps in other populations as well.
Perceived risk from occupational stress: a survey of 15 European countries: Table 1
Authors: Daniels K 
Published: April 2004

Aims:To examine the ranking of workers in 15 European countries with respect to the extent that work is perceived to influence occupational stress.Methods:International interviewer administered cross-sectional survey. Control variables included demographics, perceived job conditions, and job satisfaction. A sample of working adults (n = 11 054) from 15 European countries were studied.Results:In three statistical models, the British sample ranked in the lower half of the distribution, where higher rankings indicated greater perceived risk of occupational stress. The Greek sample was ranked first in all models, and the Irish sample ranked last in all models.Conclusions:Since there is sociocultural variation in the perceived risk from occupational stress, it is possible that sociocultural factors influence the accuracy of national monitoring systems and the success of occupational health policy in this area.
Cancer incidence and mortality of isocyanate exposed workers from the Swedish polyurethane foam industry: updated findings 1959–98
Authors: Mikoczy Z , Welinder H , Tinnerberg H , Hagmar L 
Published: April 2004

Aims:To assess whether cancer incidence and mortality in chronic obstructive lung diseases were increased in the Swedish polyurethane foam industry cohort, updated with 11 more years of follow up.Methods:The mortality and cancer incidence (1959–98) experienced by a cohort of 4175 male and female employees employed for at least one year in the period 1959–87 at one of nine Swedish polyurethane foaming plants were investigated. Comparisons were based on calendar year, sex, and five-year age group specific mortality and incidence rates for Sweden. Workplaces and job tasks were categorically assessed for exposure to toluene diisocyanate (TDI) and methylene diphenyldiisocyanate (MDI) by occupational hygienists.Results:Fewer cancer cases than expected were observed, but the lung cancer incidence was enhanced in women. Women with “apparent exposure” to TDI or MDI did not, however, have a higher lung cancer incidence than those with “no or low exposure”. Moreover, a nested case referent study did not find that polyurethane dust exposure had been more prevalent among the female lung cancer cases than among referents. No increased mortality in chronic obstructive lung diseases was observed in the cohort.Conclusions:Results support the findings from two other cohort studies of an increased lung cancer risk among female workers in the polyurethane foam manufacturing industry. Chance or confounding from smoking are not obvious explanations for the coherent findings. However, the study was not able to link isocyanate exposed employment with lung cancer risk.
Changing trends in US mesothelioma incidence
Authors: Weill H , Hughes J M , Churg A M 
Published: April 2004

Aims:To report the temporal pattern and change in trend of mesothelioma incidence in the United States since 1973.Methods:The Surveillance, Epidemiology, and End Results (SEER) programme of the National Cancer Institute has since 1973 provided annual age adjusted incidence for mesothelioma in representative cancer registries dispersed throughout the USA. SEER data are analysed to describe the trend of male mesothelioma incidence in the USA.Results:The US male mesothelioma incidence data indicate that after two decades of increasing incidence, a likely decline has been observed since the early 1990s, when a highly significant change in the upward course occurred.Conclusions:Increasing male mesothelioma incidence for many years was undoubtedly the result of exposure to asbestos. The high mesothelioma risk was prominently influenced by exposure to amphibole asbestos (crocidolite and amosite), which reached its peak usage in the 1960s and thereafter declined. A differing pattern in some other countries (continuing rise in incidence) may be related to their greater and later amphibole use, particularly crocidolite. The known latency period for the development of this tumour provides biological plausibility for the recent decline in mesothelioma incidence in the USA. This favourable finding is contrary to a widespread fear that asbestos related health effects will show an inevitable increase in coming years, or even decades.
Quantitative analysis of phagolysosome fusion in intact cells: inhibition by mycobacterial lipoarabinomannan and rescue by an 1α,25-dihydroxyvitamin D3–phosphoinositide 3-kinase pathway
Authors: Hmama Zakaria , Sendide Khalid , Talal Amina , Garcia Rosa , Dobos Karen , Reiner Neil E. 
Published: April 2004

Macrophage cell membranes were labeled with PKH26 and subsequently incubated with latex beads to generate phagosomes surrounded by a red-fluorescent membrane suitable for flow cytometry. Following cell disruption and partial purification of phagosomes, these vesicles were readily distinguished from both cell debris and free beads released from disrupted vacuoles. Flow cytometry analysis of phagosomes stained with specific mAbs and FITC-labeled secondary antibodies showed progressive acquisition of both Rab7 and LAMP-1 consistent with movement along the endocytic pathway. Alternatively, macrophages were preloaded with the lysosomal tracer FITC-dextran before membrane labeling with PKH and incubation with latex beads. Phagosome-lysosome fusion was then quantified on the basis of the colocalization of red and green signals. Using these flow cytometry-based systems, we showed that co-internalization of beads with lysates of Mycobacterium tuberculosis, but not lysates from the nonpathogenic organism Mycobacterium smegmatis, markedly decreased phagosome acquisition of Rab7 and LAMP-1 and vesicle fusion with FITC-dextran-loaded lysosomes. Inhibition of phagolysosome fusion could be attributed, at least in part, to the mycobacterial cell wall glycolipid lipoarabinomannan, and further analysis showed complete rescue of phagosome maturation when cells were pretreated with vitamin D3 before exposure to lipoarabinomannan. Moreover, the ability of vitamin D3 to reverse the phenotype of phagosomes in the presence of the glycolipid was completely abrogated by LY-294002, suggesting that vitamin D3 promotes phagolysosome fusion via a phosphoinositide 3-kinase signaling pathway.These findings establish a robust platform technology based on labeling of phagocyte cell membranes and flow cytometry capable of supporting broad-based screens to identify microbial and other bioactive compounds that influence phagosome biology.
The Insulin Resistance Syndrome
Authors: Yki-Järvinen Hannele 
Published: April 2004

AbstractRecognition of the insulin resistance syndrome is clinically important as it predicts both type 2 diabetes and cardiovascular disease. NCEP and WHO have recently published formal definitions that may help identification of the syndrome. Given the large variation of the prevalence and features of the insulin resistance syndrome, the definitions are oversimplifications as they attempt to define a biological continuous phenomenon by fixed numbers, which are unlikely to be equally useful in risk prediction in different ethnic groups. Clinical judgement therefore remains essential in assessing individuals at risk. Such risk assessment obviously also include cardiovascular risk factors such as gender, ethnicity, low‐density lipoprotein cholesterol, smoking, and family history of cardiovascular disease.
Glycated Hemoglobin and Serum Proteins as Tools for Monitoring
Authors: Goldstein Barry J. , Jabbour Serge , Ahmed Intekhab 
Published: April 2004

AbstractTechnological advances have greatly improved our ability to monitor glycemic control in patients with diabetes. To this end, one of the most important clinical advances that has improved modern diabetes care is the recognition that glucose undergoes nonenzymatic chemical reactions with various proteins in the blood, including hemoglobin, in a manner that allows the estimation of an integrated value of the glucose excursions over a period of weeks to months, providing a useful window for glucose monitoring using the hemoglobin A1c(HbA1c). The early 1980s also saw the emergence of a second group of tests, collectively called “fructosamine,” which were based on a determination of glycated serum proteins, especially albumin, and found to be useful for similar clinical purposes over a shorter time period (2–3 weeks) compared to the HbA1c. There has also been growing interest in utilizing measurement of advanced glycosylation end products (AGEs) in serum and in tissues as laboratory correlates of some of the chronic tissue damage observed in patients with diabetes. In the present chapter, starting from a chemical description of the glycation reactions, we will present the pathophysiological background necessary for an understanding of the variety of tests now used for glycated hemoglobin and albumin determination and their interpretation in different clinical encounters. Finally, we will describe AGEs and their potential relationship to the chronic complications of diabetes.