bluuebunny/crossref_metadata_2025_split huggingface dataset:
Older peoples’ perceptions of oral health: ‘it’s just not that simple’
Authors: McKenzie‐Green B , Giddings LS , Buttle L , Tahana K 
Published: January 2009

Abstract:  Objectives:  Little is known about older persons’ perceptions of oral health and oral health care. The purpose of this study was to explore the viewpoint of older adults’ regarding their oral health care practices.Methods:  A qualitative interpretive methodology was employed comprising three analytic levels: coding of data into concepts, analysis of concepts into themes, followed by an in‐depth analysis of relationships within concepts and between themes. In‐depth individual interviews were conducted with 19 participants aged 65 to 87 years.Results:  Older people’s decision to access oral health care involves complex and personally meaningful strategies. A dental visit surfaces hopes and fears based on past and present experiences. Mouth and teeth are not merely objects of dental care; they represent a person’s social and relational self. Age‐related changes challenge the relational self as represented in societal ideal images of youth and perfection (the perfect smile). This study highlights older peoples’ resilience and determination when faced with the dilemmas in accessing oral health care – it costs, personally as well as financially. Contrary to the assumption that older peoples’ oral health status is related to neglect, rather for many, it is the result of the intersection of their history with technological advances.Conclusions:  These findings challenge oral health care practitioners to be sensitive to the contexts affecting their older client’s oral health care status. They do not ‘just go’ to the dentist; they bring with them their past dental experiences and their hopes for the future. It matters how one is treated at this vulnerable time.
Tobacco use in relation to socioeconomic factors and dental care habits among Swedish individuals 15–70 years of age, 1983–2003
Authors: Hellqvist L , Rolandsson M , Birkhed D , Hugoson A 
Published: January 2009

Abstract:  Objectives:  The aim of this study was to describe the use of tobacco and changes in its use over time among individuals living in Jönköping, Sweden, and to analyse tobacco habits in relation to socioeconomic conditions, personality aspects and dental care habits.Methods:  This study comprised three epidemiological cross‐sectional studies, involving a random selection of individuals aged between 15 and 70 years, and was conducted in 1983, 1993 and 2003. The participants were asked to complete a questionnaire.Results:  The results revealed a statistically significant reduction from 34% tobacco users in 1983 to 27% in 1993 and 28% in 2003. The main decrease was seen among smokers. At the same time, the number of users of snuff increased in all the age groups between 20 and 60 years of age. The use of tobacco was therefore largely unchanged in 1993 and 2003. In 2003, there was a statistically significant difference between users and non‐tobacco users when it came to the frequency of dental visits; more tobacco users than non‐tobacco users did not visit a dentist at all or did not visit a dentist regularly. In 1993, non‐tobacco users brushed their teeth more frequently than tobacco users and this difference was statistically significant.Conclusions:  During the 20‐year study, there was a reduction in the number of smokers and an increase in the number of snuff users. There was a difference between tobacco users and non‐tobacco users when it came to the frequency of dental visits and oral hygiene habits.
Smoking and caries experience in subjects with various form of periodontal diseases from a teaching hospital clinic
Authors: Al‐Habashneh R , Al‐Omari MAO , Taani DQ 
Published: January 2009

Abstract:  Objective:  The aim of this study was to assess the relationships between aggressive periodontitis (AgP), caries and smoking.Method and materials:  A cross‐sectional study was conducted among patients who were specifically referred to the Dental Teaching Clinic in Irbid, Jordan for periodontal treatment. Self‐administered questionnaire related to socio‐demographic data and smoking habits was completed. The oral hygiene, gingival status, periodontal health and dental status of the participants was determined by using the plaque index of Silness and Loe [Acta Odontol Scand, 22 (1964), 121], the gingival index of Loe and Silness [Acta Odontol Scand, 21 (1963), 233], clinical attachment level (CAL) and decayed, missing and filled teeth (DMFT) index respectively.Result:  The prevalence of smoking was greater in chronic periodontitis (CP) group (44.2%) than in either chronic gingivitis (CG) (27.4%) or AgP (29.9%) group. Self‐reported perio‐diseases in the close family was more prevalent (77%) among subjects diagnosed with AgP. The mean plaque scores were significantly higher for smoker than non‐smoker in AgP group only (P = 0.04), with significantly greater plaque and gingival scores in CG and CP groups than AgP group (P = 0.012, 0.004). A significantly greater mean gingival scores were noted among CG and CP groups than AgP group (P = 0.004). The mean CAL was higher in smokers than in non‐smokers in the three groups, with statistically significant differences in CP and AgP groups (P = 0.04, 0.01 respectively).The mean number of DMFT was significantly higher in smoker than in non‐smoker of all age groups (P = 0.016, 0.043 and 0.01). However, mean DMFT was significantly greater in CP and CG than AgP groups.Conclusion:  It was concluded that (i) higher plaque and gingival index among smokers in all groups; (ii) significant difference in the CAL between smoker and non‐smoke in CP and AgP groups; (iii) significant increase in caries risk among smokers in all groups; (iv) smokers and non‐smokers of AgP group had significantly lower mean DMFT scores than those of CG or CP groups.
Studies of the Production of Fungal Polyketides inAspergillus nidulansby Using Systems Biology Tools
Authors: Panagiotou Gianni , Andersen Mikael R. , Grotkjaer Thomas , Regueira Torsten B. , Nielsen Jens , Olsson Lisbeth 
Published: January 2009

ABSTRACTMany filamentous fungi produce polyketide molecules with great significance as human pharmaceuticals; these molecules include the cholesterol-lowering compound lovastatin, which was originally isolated fromAspergillus terreus. The chemical diversity and potential uses of these compounds are virtually unlimited, and it is thus of great interest to develop a well-described microbial production platform for polyketides. Using genetic engineering tools available for the model organismAspergillus nidulans, we constructed two recombinant strains, one expressing thePenicillium griseofulvum6-methylsalicylic acid (6-MSA) synthase gene and one expressing the 6-MSA synthase gene and overexpressing the native xylulose-5-phosphate phosphoketolase gene (xpkA) for increasing the pool of polyketide precursor levels. The physiology of the recombinant strains and that of a reference wild-type strain were characterized on glucose, xylose, glycerol, and ethanol media in controlled bioreactors. Glucose was found to be the preferred carbon source for 6-MSA production, and 6-MSA concentrations up to 455 mg/liter were obtained for the recombinant strain harboring the 6-MSA gene. Our findings indicate that overexpression ofxpkAdoes not directly improve 6-MSA production on glucose, but it is possible, if the metabolic flux through the lower part of glycolysis is reduced, to obtain quite high yields for conversion of sugar to 6-MSA. Systems biology tools were employed for in-depth analysis of the metabolic processes. Transcriptome analysis of 6-MSA-producing strains grown on glucose and xylose in the presence and absence ofxpkAoverexpression, combined with flux and physiology data, enabled us to propose anxpkA-msaSinteraction model describing the competition between biomass formation and 6-MSA production for the available acetyl coenzyme A.
Changes in Barotolerance, Thermotolerance, and Cellular Morphology throughout the Life Cycle of
Listeria monocytogenes
Authors: Wen Jia , Anantheswaran Ramaswamy C. , Knabel Stephen J. 
Published: January 2009

ABSTRACT

Changes in barotolerance, thermotolerance, and cellular morphology throughout the life cycle of
Listeria monocytogenes
were investigated. For part 1 of this analysis,
L. monocytogenes
ATCC 19115 was grown to log, stationary, death, and long-term-survival phases at 35°C in tryptic soy broth with yeast extract (TSBYE). Cells were diluted in whole milk that had been subjected to ultrahigh temperatures (UHT whole milk) and then high-pressure processed (HPP) at 400 MPa for 180 s or thermally processed at 62.8°C for 30 s. As cells transitioned from the log to the long-term-survival phase, the D
400 MPa
and D
62.8°C
values increased 10- and 19-fold, respectively. Cells decreased in size as they transitioned from the log to the long-term-survival phase. Rod-shaped cells transitioned to cocci as they entered the late-death and long-term-survival phases.
L. monocytogenes
strains F5069 and Scott A showed similar results. For part 2 of the analysis, cells in long-term-survival phase were centrifuged, suspended in fresh TSBYE, and incubated at 35°C. As cells transitioned from the long-term-survival phase to log and the stationary phase, they increased in size and log reductions increased following HPP or heat treatment. In part 3 of this analysis, cells in long-term-survival phase were centrifuged, suspended in UHT whole milk, and incubated at 4°C. After HPP or heat treatment, similar results were observed as for part 2. We hypothesize that cells of
L. monocytogenes
enter a dormant, long-term-survival phase and become more barotolerant and thermotolerant due to cytoplasmic condensation when they transition from rods to cocci. Further research is needed to test this hypothesis and to determine the practical significance of these findings.
Longitudinal Study of Shiga Toxin-Producing
Escherichia coli
Shedding in Sheep Feces: Persistence of Specific Clones in Sheep Flocks
Authors: Sánchez Sergio , Martínez Remigio , García Alfredo , Blanco Jorge , Blanco Jesús E. , Blanco Miguel , Dahbi Ghizlane , López Cecilia , Mora Azucena , Rey Joaquín , Alonso Juan M. 
Published: January 2009

ABSTRACT

To provide information on the persistence and maintenance of colonization with Shiga toxin-producing
Escherichia coli
(STEC) in sheep, pulsed-field gel electrophoresis analysis of STEC isolates (
n
= 145) belonging to serogroups O5, O91, and O146 from 39 healthy animals was performed in a 12-month longitudinal study carried out with four sheep flocks. At the flock level as well as the individual-animal level, the same clones were obtained on sampling occasions separated by as much as 11 months.
Reconfiguring the Quorum-Sensing Regulator SdiA ofEscherichia coliTo Control Biofilm Formation via Indole andN-Acylhomoserine Lactones
Authors: Lee Jintae , Maeda Toshinari , Hong Seok Hoon , Wood Thomas K. 
Published: January 2009

ABSTRACTSdiA is a homolog of quorum-sensing regulators that detectsN-acylhomoserine lactone (AHL) signals from other bacteria.Escherichia coliuses SdiA to reduce its biofilm formation in the presence of both AHLs and its own signal indole. Here we reconfigured SdiA (240 amino acids) to control biofilm formation using protein engineering. Four SdiA variants were obtained with altered biofilm formation, including truncation variants SdiA1E11 (F7L, F59L, Y70C, M94K, and K153X) and SdiA14C3 (W9R, P49T, N87T, frameshift at N96, and L123X), which reduced biofilm formation by 5- to 20-fold compared to wild-type SdiA in the presence of endogenous indole. Whole-transcriptome profiling revealed that wild-type SdiA reduced biofilm formation by repressing genes related to indole synthesis and curli synthesis compared to when no SdiA was expressed, while variant SdiA1E11 induced genes related to indole synthesis in comparison to wild-type SdiA. These results suggested altered indole metabolism, and corroborating the DNA microarray results in regard to indole synthesis, variant SdiA1E11 produced ninefold more indole, which led to reduced swimming motility and cell density. Also, wild-type SdiA decreased curli production andtnaAtranscription, while SdiA1E11 increasedtnaAtranscription (tnaAencodes tryptophanase, which forms indole) compared to wild-type SdiA. Hence, wild-type SdiA decreased biofilm formation by reducing curli production and motility, and SdiA1E11 reduced biofilm formation via indole. Furthermore, an AHL-sensitive variant (SdiA2D10, having four mutations at E31G, Y42F, R116H, and L165Q) increased biofilm formation sevenfold in the presence ofN-octanoyl-dl-homoserine lactone andN-(3-oxododecatanoyl)-l-homoserine lactone. Therefore, SdiA can be evolved to increase or decrease biofilm formation, and biofilm formation may be controlled by altering sensors rather than signals.
Real-Time PCR Assay for Detection of a New Simulant for Poxvirus Biothreat Agents
Authors: Garnier Laurence , Gaudin Jean-Christophe , Bensadoun Paul , Rebillat Isabelle , Morel Yannick 
Published: January 2009

ABSTRACT

Research and financial efforts spent on biodefense technologies highlight the current concern for biothreat event preparedness. Nonhazardous but relevant “simulant” microorganisms are typically used to simplify technological developments, testing, and staff training. The bacteriophage MS2, a small RNA virus, is classically used as the reference simulant for biothreat viruses within the biodefense community. However, variola virus, considered a major threat, displays very different features (size, envelope, and double-stranded DNA genome). The size parameter is critical for aerosol sampling, detection, and protection/filtration technologies. Therefore, a panel of relevant simulants should be used to cover the diversity of biothreat agents. Thus, we investigated a new virus model, the
Cydia pomonella
granulovirus (baculovirus), which is currently used as a biopesticide. It displays a size similar to that of poxviruses, is enveloped, and contains double-stranded DNA. To provide a molecular tool to detect and quantify this model virus, we developed an assay based on real-time PCR, with a limit of detection ranging from roughly 10 to a few tens of target copies per μl according to the sample matrix. The specificity of the assay against a large panel of potential cross-reactive microorganisms was checked, and the suitability of the assay for environmental samples, especially aerosol studies, was determined. In conclusion, we suggest that our PCR assay allows
Cydia pomonella
granulovirus to be used as a simulant for poxviruses. This assay may also be useful for environmental or crop treatment studies.
Development of a Prophage Typing System and Analysis of Prophage Carriage in
Streptococcus pneumoniae
Authors: Romero Patricia , García Ernesto , Mitchell Tim J. 
Published: January 2009

ABSTRACT

The frequency of prophage carriage was tested in a collection of 108 clinical isolates of
Streptococcus pneumoniae
. A PCR-based assay was developed to allow classification of the prophage into the three groups recently identified according to genome comparisons (P. Romero, N. Croucher, N. L. Hiller, F. Z. Hu, G. D. Ehrlich, S. D. Bentley, E. García, and T. J. Mitchell, submitted for publication). Use of the assay showed that more than half of the isolates studied were lysogenic with prophage belonging to group 1 being the most abundant (56%), followed by those belonging to group 2 (26%) and those belonging to group 3 (11%). Four polylysogenic strains harboring a group 1 and a group 2 prophage were identified. Interestingly, lysogenic strains were found in 8 out of the 12 internationally distributed, relevant clones of
S. pneumoniae
contained in our strain collection. The high percentage of clinical pneumococcal isolates harboring prophage strongly suggests an important contribution to the diversification of the genome architecture in this species as well as a role for bacteriophage in the virulence/and or fitness of
S. pneumoniae
, although further studies using a significant number of isolates belonging to the most relevant pneumococcal clones are needed.
Nickel Promotes Biofilm Formation by
Escherichia coli
K-12 Strains That Produce Curli
Authors: Perrin Claire , Briandet Romain , Jubelin Gregory , Lejeune Philippe , Mandrand-Berthelot Marie-Andrée , Rodrigue Agnès , Dorel Corinne 
Published: January 2009

ABSTRACT

The survival of bacteria exposed to toxic compounds is a multifactorial phenomenon, involving well-known molecular mechanisms of resistance but also less-well-understood mechanisms of tolerance that need to be clarified. In particular, the contribution of biofilm formation to survival in the presence of toxic compounds, such as nickel, was investigated in this study. We found that a subinhibitory concentration of nickel leads
Escherichia coli
bacteria to change their lifestyle, developing biofilm structures rather than growing as free-floating cells. Interestingly, whereas nickel and magnesium both alter the global cell surface charge, only nickel promotes biofilm formation in our system. Genetic evidence indicates that biofilm formation induced by nickel is mediated by the transcriptional induction of the adhesive curli-encoding genes. Biofilm formation induced by nickel does not rely on efflux mechanisms using the RcnA pump, as these require a higher concentration of nickel to be activated. Our results demonstrate that the nickel-induced biofilm formation in
E. coli
is an adaptational process, occurring through a transcriptional effect on genes coding for adherence structures. The biofilm lifestyle is obviously a selective advantage in the presence of nickel, but the means by which it improves bacterial survival needs to be investigated.
Tetracycline Resistome of the Organic Pig Gut
Authors: Kazimierczak Katarzyna A. , Scott Karen P. , Kelly Denise , Aminov Rustam I. 
Published: January 2009

ABSTRACT

The occurrence of genes conferring resistance to tetracyclines in the organic pig gut was assessed through the metagenomic approach. Of 9,000 bacterial artificial chromosome clones analyzed, 10 were identified as carrying the known
tet
(C),
tet
(W), and
tet
(40) genes, as well as novel genes encoding resistance to the tetracyclines minocycline and doxycycline. The latter are different from the known
tet
genes and are homologous to genes encoding UDP-glucose 4-epimerases, with the domain structure characteristic for these enzymes. The majority of the resistance genes were associated with putative mobile genetic elements. The sequence of a novel 9.7-kb plasmid carrying
tet
(W) and
tet
(40) was also identified. Conserved flanking regions identified around the
tet
(W) and
tet
(40) genes in our metagenomic library may play a role in genetic exchange of these genes. This is the first report describing the occurrence of
tet
(40) outside the human intestine. The maintenance of antibiotic resistance genes in apparently antibiotic-free animals is probably due to their presence on mobile genetic elements, the fitness cost of which for the cell is ameliorated during the previous antibiotic selection.
Exploring the Diversity of the Bifidobacterial Population in the Human Intestinal Tract
Authors: Turroni Francesca , Foroni Elena , Pizzetti Paola , Giubellini Vanessa , Ribbera Angela , Merusi Paolo , Cagnasso Patrizio , Bizzarri Barbara , de'Angelis Gian Luigi , Shanahan Fergus , van Sinderen Douwe , Ventura Marco 
Published: January 2009

ABSTRACT

Although the health-promoting roles of bifidobacteria are widely accepted, the diversity of bifidobacteria among the human intestinal microbiota is still poorly understood. We performed a census of bifidobacterial populations from human intestinal mucosal and fecal samples by plating them on selective medium, coupled with molecular analysis of selected rRNA gene sequences (16S rRNA gene and internally transcribed spacer [ITS] 16S-23S spacer sequences) of isolated colonies. A total of 900 isolates were collected, of which 704 were shown to belong to bifidobacteria. Analyses showed that the culturable bifidobacterial population from intestinal and fecal samples include six main phylogenetic taxa, i.e.,
Bifidobacterium longum
,
Bifidobacterium pseudocatenulatum
,
Bifidobacterium adolescentis
,
Bifidobacterium pseudolongum
,
Bifidobacterium breve
, and
Bifidobacterium bifidum
, and two species mostly detected in fecal samples, i.e.,
Bifidobacterium dentium
and
Bifidobacterium animalis
subp.
lactis
. Analysis of bifidobacterial distribution based on age of the subject revealed that certain identified bifidobacterial species were exclusively present in the adult human gut microbiota whereas others were found to be widely distributed. We encountered significant intersubject variability and composition differences between fecal and mucosa-adherent bifidobacterial communities. In contrast, a modest diversification of bifidobacterial populations was noticed between different intestinal regions within the same individual (intrasubject variability). Notably, a small number of bifidobacterial isolates were shown to display a wide ecological distribution, thus suggesting that they possess a broad colonization capacity.
Comparative Analysis of Attachment of Shiga-Toxigenic
Escherichia coli
and
Salmonella
Strains to Cultured HT-29 and Caco-2 Cell Lines
Authors: Mellor Glen E. , Goulter Rebecca M. , Chia T. W. Raymond , Dykes Gary A. 
Published: January 2009

ABSTRACT

The ability of
Escherichia coli
and
Salmonella
isolates to attach to Caco-2 and HT-29 cell monolayers was measured. All isolates displayed a greater ability to attach to Caco-2 cells than HT-29 cells, and overall
E. coli
isolates attached better to both cell lines than
Salmonella
isolates. Bacteria that were considered to be pathogenic displayed no greater ability to attach to cell lines than those that were not considered to be pathogenic. Additionally, no correlation was found between cell line attachment and previously determined hydrophobicity results.
Phage-Mediated Shiga Toxin 2 Gene Transfer in Food and Water
Authors: Imamovic Lejla , Jofre Juan , Schmidt Herbert , Serra-Moreno Ruth , Muniesa Maite 
Published: January 2009

ABSTRACT

Shiga toxin (
stx
) transduction in various food matrices has been evaluated with lysogens of Stx phages.
stx
transduction events were observed for many phages under appropriate conditions. Transduction did not occur at low pH and low temperatures. A total of 10
3
to 10
4
CFU ml
−1
was the minimal amount of donor and recipient strains necessary to generate transductants.
Diffusion of Macromolecules in Model Oral Biofilms
Authors: Takenaka Shoji , Pitts Betsey , Trivedi Harsh M. , Stewart Philip S. 
Published: January 2009

ABSTRACT
The diffusive penetration of fluorescently tagged macromolecular solutes into model oral biofilms was visualized by time-lapse microscopy. All of the solutes tested, including dextrans, proteases, green fluorescent protein, and immunoglobulin G, accessed the interior of cell clusters 100 to 200 μm in diameter within 3 min or less.
C
29
Olefinic Hydrocarbons Biosynthesized by
Arthrobacter
Species
Authors: Frias Janice A. , Richman Jack E. , Wackett Lawrence P. 
Published: January 2009

ABSTRACT

Arthrobacter aurescens
TC1,
Arthrobacter chlorophenolicus
A6,
Arthrobacter crystallopoietes
, and
Arthrobacter oxydans
produce long-chain monoalkenes, predominantly
cis
-3,25-dimethyl-13-heptacosene. Four other
Arthrobacter
strains did not form alkenes. The level of
cis
-3,25-dimethyl-13-heptacosene in
Arthrobacter chlorophenolicus
A6 remained proportional to cell mass during growth.
cis
-3,25-Dimethyl-13-heptacosene did not support growth of
A. chlorophenolicus
A6.