bluuebunny/crossref_metadata_2025_split huggingface dataset:
Novelty Seeking as a Moderator of Familial Risk for Alcohol Dependence
Authors: Grucza Richard A. , Robert Cloninger C. , Bucholz Kathleen K. , Constantino John N. , Schuckit Marc I. , Dick Danielle M. , Bierut Laura J. 
Published: June 2006

Background: Disinhibitory personality traits such as high novelty seeking (NS) are moderately heritable, and individuals with substance use disorders (SUDs) frequently exhibit such traits. However, recent studies have cast doubt on the supposition that such traits are true familial risk factors for SUD and particularly for alcohol dependence. Another possibility is that familial risk interacts with personality‐associated risk, in which case the association between personality and familial risk might depend on sample composition, accounting for the lack of consensus among studies to date. We examined this possibility by analyzing the association between NS and alcohol dependence in individuals at intermediate and high levels of familial risk for alcohol dependence.Methods: Data from the Collaborative Study on the Genetics of Alcoholism, a multisite family study, were examined. Subjects were 1,111 adult siblings of alcohol‐dependent index cases. Parental diagnoses of alcohol dependence and personality scores of NS from the Tridimensional Personality Questionnaire were used to predict alcohol dependence.Results: A significant interaction between NS and familial risk for alcoholism was seen, such that NS was a significantly stronger predictor of alcohol dependence in subjects with one or more parents with alcohol dependence than in subjects without alcohol‐dependent parents.Conclusions: Novelty seeking and familial risk interact so that the risk associated with high NS is magnified in families with parental alcohol dependence and NS is a moderator of familial risk. Accordingly, high NS is strongly associated with alcohol dependence in subjects with a parent diagnosed with alcohol dependence, but low NS may protect against the risk associated with familial alcoholism. This interaction may account for conflicting findings from studies that have examined this question previously.
Healing of intrabony peri‐implantitis defects following application of a nanocrystalline hydroxyapatite (Ostim™) or a bovine‐derived xenograft (Bio‐Oss™) in combination with a collagen membrane (Bio‐Gide™). A case series
Authors: Schwarz F. , Bieling K. , Latz T. , Nuesry E. , Becker J. 
Published: June 2006

AbstractObjectives: The aim of the present case series was to evaluate the healing of intrabony peri‐implantitis defects following application of a nanocrystalline hydroxyapatite (NHA) or a bovine‐derived xenograft in combination with a collagen membrane (BDX+BG).Material and Methods: Twenty‐two patients having moderate peri‐implantitis (n=22 intrabony defects) were randomly treated with (i) access flap surgery (AFS) and the application of NHA, or with AFS and the application of BDX+BG. Clinical parameters were recorded at baseline and after 6 months of non‐submerged healing.Results: Post‐operative wound healing revealed that NHA compromized initial adhesion of the mucoperiosteal flaps in all patients. At 6 months after therapy, NHA showed a reduction in the mean PD from 7.0 ± 0.6 to 4.9 ± 0.6 mm and a change in the mean clinical attachment loss (CAL) from 7.5 ± 0.8 to 5.7 ± 1.0 mm. In the BDX+BC group, the mean PD was reduced from 7.1 ± 0.8 to 4.5 ± 0.7 mm and the mean CAL changed from 7.5 ± 1.0 to 5.2 ± 0.8 mm.Conclusion: Within the limits of the present case series, it can be concluded that at 6 months after surgery both therapies resulted in clinically important PD reductions and CAL gains.
Breastfeeding and family life
Authors: Lavender Tina , McFadden Catherine , Baker Lisa 
Published: June 2006

AbstractThe problems faced by breastfeeding mothers are well documented. However, the influence of social networks has mainly received attention solely through the eyes of the women. Therefore, we explored the views of the family as a whole. This exploratory study utilizes semi‐structured interviews, diaries and questionnaires. A purposive sample of 24 women and their families, from a hospital in the north‐west of England were invited to participate. Questionnaire data were analysed descriptively. Diaries and interviews were analysed using an open coding mechanism to identify emergent themes. Twenty‐three women and 27 of their family members participated. Questionnaire data showed that the majority of women (n = 17) expected to breastfeed for more than 3 months; 12 actually did this. Women anticipated that family members would provide the main source of breastfeeding support. Three main themes emerged from the interviews and diaries: ‘moving with the times’, ‘marketable commodity’ and ‘disparate communications’. The authors conclude that multi‐layered approach to breastfeeding promotion and support should be considered. Society needs to proactively encourage a positive breastfeeding culture, family members need direction on how to support a woman to breastfeed and women need to be able to articulate their individual requirements. Midwives could be instrumental in supporting such needs and facilitating change.
Effect of Repeat Copy Number on Variable-Number Tandem Repeat Mutations in
Escherichia coli
O157:H7
Authors: Vogler Amy J. , Keys Christine , Nemoto Yoshimi , Colman Rebecca E. , Jay Zack , Keim Paul 
Published: June 2006

ABSTRACT

Variable-number tandem repeat (VNTR) loci have shown a remarkable ability to discriminate among isolates of the recently emerged clonal pathogen
Escherichia coli
O157:H7, making them a very useful molecular epidemiological tool. However, little is known about the rates at which these sequences mutate, the factors that affect mutation rates, or the mechanisms by which mutations occur at these loci. Here, we measure mutation rates for 28 VNTR loci and investigate the effects of repeat copy number and mismatch repair on mutation rate using in vitro-generated populations for 10
E. coli
O157:H7 strains. We find single-locus rates as high as 7.0 × 10
−4
mutations/generation and a combined 28-locus rate of 6.4 × 10
−4
mutations/generation. We observed single- and multirepeat mutations that were consistent with a slipped-strand mispairing mutation model, as well as a smaller number of large repeat copy number mutations that were consistent with recombination-mediated events. Repeat copy number within an array was strongly correlated with mutation rate both at the most mutable locus, O157-10 (
r
2
= 0.565,
P
= 0.0196), and across all mutating loci. The combined locus model was significant whether locus O157-10 was included (
r
2
= 0.833,
P
< 0.0001) or excluded (
r
2
= 0.452,
P
< 0.0001) from the analysis. Deficient mismatch repair did not affect mutation rate at any of the 28 VNTRs with repeat unit sizes of >5 bp, although a poly(G) homomeric tract was destabilized in the
mutS
strain. Finally, we describe a general model for VNTR mutations that encompasses insertions and deletions, single- and multiple-repeat mutations, and their relative frequencies based upon our empirical mutation rate data.
Mutations and Rearrangements in the Genome ofSulfolobus solfataricusP2
Authors: Redder Peter , Garrett Roger A. 
Published: June 2006

ABSTRACTThe genome ofSulfolobus solfataricusP2 carries a larger number of transposable elements than any other sequenced genome from an archaeon or bacterium and, as a consequence, may be particularly susceptible to rearrangement and change. In order to gain more insight into the natures and frequencies of different types of mutation and possible rearrangements that can occur in the genome, thepyrEFlocus was examined for mutations that were isolated after selection with 5-fluoroorotic acid. About two-thirds of the 130 mutations resulted from insertions of mobile elements, including insertion sequence (IS) elements and a single nonautonomous mobile element, SM2. For each of these, the element was identified and shown to be present at its original genomic position, consistent with a progressive increase in the copy numbers of the mobile elements. In addition, several base pair substitutions, as well as small deletions, insertions, and a duplication, were observed, and about one-fifth of the mutations occurred elsewhere in the genome, possibly in an orotate transporter gene. One mutant exhibited a 5-kb genomic rearrangement at thepyrEFlocus involving a two-step IS element-dependent reaction, and its boundaries were defined using a specially developed “in vitro library” strategy. Moreover, while searching for the donor mobile elements, evidence was found for two major changes that had occurred in the genome of strain P2, one constituting a single deletion of about 4% of the total genome (124 kb), while the other involved the inversion of a 25-kb region. Both were bordered by IS elements and were inferred to have arisen through recombination events. The results underline the caution required in working experimentally with an organism such asS. solfataricuswith a continually changing genome.
Transcriptional and Translational Control of the
Salmonella fliC
Gene
Authors: Aldridge Phillip , Gnerer Joshua , Karlinsey Joyce E. , Hughes Kelly T. 
Published: June 2006

ABSTRACT

The flagellin gene
fliC
encodes the major component of the flagellum in
Salmonella enterica
serovar Typhimurium. This study reports the identification of a signal within the 5′ untranslated region (5′UTR) of the
fliC
transcript required for the efficient expression and assembly of FliC into the growing flagellar structure. Primer extension mapping determined the transcription start site of the
fliC
flagellin gene to be 62 bases upstream of the AUG start codon. Using
tetA-fliC
operon fusions, we show that the entire 62-base 5′UTR region of
fliC
was required for sufficient
fliC
mRNA translation to allow normal FliC flagellin assembly, suggesting that translation might be coupled to assembly. To identify sequence that might couple
fliC
mRNA translation to FliC secretion, the 5′ end of the chromosomal
fliC
gene was mutagenized by PCR-directed mutagenesis. Single base sequences important for
fliC
-dependent transcription, translation, and motility were identified by using
fliC-lacZ
transcriptional and translational reporter constructs. Transcription-specific mutants identified the −10 and −35 regions of the consensus flagellar class 3 gene promoter. Single base changes defective in translation were located in three regions: the AUG start codon, the presumed ribosomal binding site region, and a region near the very 5′ end of the
fliC
mRNA that corresponded to a potential stem-loop structure in the 5′UTR. Motility-specific mutants resulted from base substitutions only in the
fliC
-coding region. The results suggest that
fliC
mRNA translation is not coupled to FliC secretion by the flagellar type III secretion system.
Characterization of the Ends and Target Site of a Novel Tetracycline Resistance-Encoding Conjugative Transposon from
Enterococcus faecium
664.1H1
Authors: Roberts Adam P. , Davis Ian J. , Seville Lorna , Villedieu Aurelie , Mullany Peter 
Published: June 2006

ABSTRACT

Enterococcus faecium
664.1H1 is multiply antibiotic resistant and mercury resistant. In this study, the genetic support for the tetracycline resistance of
E. faecium
664.1H1 was characterized. The
tet
(S) gene is responsible for tetracycline resistance, and this gene is located on the chromosome of
E. faecium
664.1H1, on a novel conjugative transposon. The element is transferable to
Enterococcus faecalis
, where it integrates into a specific site. The element was designated EfcTn
1
. The integrase of EfcTn
1
is related to the integrase proteins found on staphylococcal pathogenicity islands. We show that the transposon is flanked by an 18-bp direct repeat, a copy of which is also present at the target site and at the joint of a circular form, and we propose a mechanism of insertion and excision.
Citric Acid Cycle in the Hyperthermophilic Archaeon
Pyrobaculum islandicum
Grown Autotrophically, Heterotrophically, and Mixotrophically with Acetate
Authors: Hu Yajing , Holden James F. 
Published: June 2006

ABSTRACT

The hyperthermophilic archaeon
Pyrobaculum islandicum
uses the citric acid cycle in the oxidative and reductive directions for heterotrophic and autotrophic growth, respectively, but the control of carbon flow is poorly understood.
P. islandicum
was grown at 95°C autotrophically, heterotrophically, and mixotrophically with acetate, H
2
, and small amounts of yeast extract and with thiosulfate as the terminal electron acceptor. The autotrophic growth rates and maximum concentrations of cells were significantly lower than those in other media. The growth rates on H
2
and 0.001% yeast extract with and without 0.05% acetate were the same, but the maximum concentration of cells was fourfold higher with acetate. There was no growth with acetate if 0.001% yeast extract was not present, and addition of H
2
to acetate-containing medium greatly increased the growth rates and maximum concentrations of cells.
P. islandicum
cultures assimilated
14
C-labeled acetate in the presence of H
2
and yeast extract with an efficiency of 55%. The activities of 11 of 19 enzymes involved in the central metabolism of
P. islandicum
were regulated under the three different growth conditions. Pyruvate synthase and acetate:coenzyme A (CoA) ligase (ADP-forming) activities were detected only in heterotrophically grown cultures. Citrate synthase activity decreased in autotrophic and acetate-containing cultures compared to the activity in heterotrophic cultures. Acetylated citrate lyase, acetate:CoA ligase (AMP forming), and phosphoenolpyruvate carboxylase activities increased in autotrophic and acetate-containing cultures. Citrate lyase activity was higher than ATP citrate synthase activity in autotrophic cultures. These data suggest that citrate lyase and AMP-forming acetate:CoA ligase, but not ATP citrate synthase, work opposite citrate synthase to control the direction of carbon flow in the citric acid cycle.
N
-Acyl-
l
-Homoserine Lactone Quorum Sensing Controls Butanediol Fermentation in
Serratia plymuthica
RVH1 and
Serratia marcescens
MG1
Authors: Van Houdt Rob , Moons Pieter , Hueso Buj Maria , Michiels Chris W. 
Published: June 2006

ABSTRACT

Butanediol fermentation in two
Serratia
species is shown to be affected by
N
-acyl-
l
-homoserine lactone-dependent quorum sensing. Knockout of quorum-sensing signal production caused a shift towards enhanced acid production, resulting in early growth arrest, which was reversible by the addition of synthetic signal molecules.
The Lipid A 1-Phosphatase ofHelicobacter pyloriIs Required for Resistance to the Antimicrobial Peptide Polymyxin
Authors: Tran An X. , Whittimore Judy D. , Wyrick Priscilla B. , McGrath Sara C. , Cotter Robert J. , Trent M. Stephen 
Published: June 2006

ABSTRACTModification of the phosphate groups of lipid A with amine-containing substituents, such as phosphoethanolamine, reduces the overall net negative charge of gram-negative bacterial lipopolysaccharide, thereby lowering its affinity to cationic antimicrobial peptides. Modification of the 1 position ofHelicobacter pylorilipid A is a two-step process involving the removal of the 1-phosphate group by a lipid A phosphatase, LpxEHP(Hp0021), followed by the addition of a phosphoethanolamine residue catalyzed by EptAHP(Hp0022). To demonstrate the importance of modifying the 1 position ofH. pylorilipid A, we generated LpxEHP-deficient mutants in variousH. pyloristrains by insertion of a chloramphenicol resistance cassette intolpxEHPand examined the significance of LpxE with respect to cationic antimicrobial peptide resistance. Using both mass spectrometry analysis and an in vitro assay system, we showed that the loss of LpxEHPactivity in variousH. pyloristrains resulted in the loss of modification of the 1 position ofH. pylorilipid A, thus confirming the function of LpxEHP. Due to its unique lipid A structure,H. pyloriis highly resistant to the antimicrobial peptide polymyxin (MIC > 250 μg/ml). However, disruption oflpxEHPinH. pyloriresults in a dramatic decrease in polymyxin resistance (MIC, 10 μg/ml). In conclusion, we have characterized the first gram-negative LpxE-deficient mutant and have shown the importance of modifying the 1 position ofH. pylorilipid A for resistance to polymyxin.
A LuxS-Dependent Cell-to-Cell Language Regulates Social Behavior and Development inBacillus subtilis
Authors: Lombardía Esteban , Rovetto Adrián J. , Arabolaza Ana L. , Grau Roberto R. 
Published: June 2006

ABSTRACTCell-to-cell communication in bacteria is mediated by quorum-sensing systems (QSS) that produce chemical signal molecules called autoinducers (AI). In particular, LuxS/AI-2-dependent QSS has been proposed to act as a universal lexicon that mediates intra- and interspecific bacterial behavior. Here we report that the model organismBacillus subtilisoperates aluxS-dependent QSS that regulates its morphogenesis and social behavior. We demonstrated thatB. subtilis luxSis a growth-phase-regulated gene that produces active AI-2 able to mediate the interspecific activation of light production inVibrio harveyi. We demonstrated that inB. subtilis,luxSexpression was under the control of a novel AI-2-dependent negative regulatory feedback loop that indicated an important role for AI-2 as a signaling molecule. Even thoughluxSdid not affect spore development, AI-2 production was negatively regulated by the master regulatory proteins of pluricellular behavior, SinR and Spo0A. Interestingly, wildB. subtiliscells, from the undomesticated and probioticB. subtilisnatto strain, required the LuxS-dependent QSS to form robust and differentiated biofilms and also to swarm on solid surfaces. Furthermore, LuxS activity was required for the formation of sophisticated aerial colonies that behaved as giant fruiting bodies where AI-2 production and spore morphogenesis were spatially regulated at different sites of the developing colony. We proposed that LuxS/AI-2 constitutes a novel form of quorum-sensing regulation where AI-2 behaves as a morphogen-like molecule that coordinates the social and pluricellular behavior ofB. subtilis.
Proteins Exported via the PrsD-PrsE Type I Secretion System and the Acidic Exopolysaccharide Are Involved in Biofilm Formation byRhizobium leguminosarum
Authors: Russo Daniela M. , Williams Alan , Edwards Anne , Posadas Diana M. , Finnie Christine , Dankert Marcelo , Downie J. Allan , Zorreguieta Angeles 
Published: June 2006

ABSTRACTThe type I protein secretion system ofRhizobium leguminosarumbv. viciae encoded by theprsDandprsEgenes is responsible for secretion of the exopolysaccharide (EPS)-glycanases PlyA and PlyB. The formation of a ring of biofilm on the surface of the glass in shaken cultures by both theprsDandprsEsecretion mutants was greatly affected. Confocal laser scanning microscopy analysis of green-fluorescent-protein-labeled bacteria showed that during growth in minimal medium,R. leguminosarumwild type developed microcolonies, which progress to a characteristic three-dimensional biofilm structure. However, theprsDandprsEsecretion mutants were able to form only an immature biofilm structure. A mutant disrupted in the EPS-glycanaseplyBgene showed altered timing of biofilm formation, and its structure was atypical. A mutation in an essential gene for EPS synthesis (pssA) or deletion of several otherpssgenes involved in EPS synthesis completely abolished the ability ofR. leguminosarumto develop a biofilm. Extracellular complementation studies of mixed bacterial cultures confirmed the role of the EPS and the modulation of the biofilm structure by the PrsD-PrsE secreted proteins. Protein analysis identified several additional proteins secreted by the PrsD-PrsE secretion system, and N-terminal sequencing revealed peptides homologous to the N termini of proteins from the Rap family (Rhizobiumadheringproteins), which could have roles in cellular adhesion inR. leguminosarum. We propose a model forR. leguminosarumin which synthesis of the EPS leads the formation of a biofilm and several PrsD-PrsE secreted proteins are involved in different aspects of biofilm maturation, such as modulation of the EPS length or mediating attachment between bacteria.
Pseudomonas aeruginosa
1244 Pilin Glycosylation: Glycan Substrate Recognition
Authors: Horzempa Joseph , Dean Charles R. , Goldberg Joanna B. , Castric Peter 
Published: June 2006

ABSTRACT

The pilin of
Pseudomonas aeruginosa
1244 is glycosylated with an oligosaccharide that is structurally identical to the O-antigen repeating unit of this organism. Concordantly, the metabolic source of the pilin glycan is the O-antigen biosynthetic pathway. The present study was conducted to investigate glycan substrate recognition in the 1244 pilin glycosylation reaction. Comparative structural analysis of O subunits that had been previously shown to be compatible with the 1244 glycosylation machinery revealed similarities among sugars at the presumed reducing termini of these oligosaccharides. We therefore hypothesized that the glycosylation substrate was within the sugar at the reducing end of the glycan precursor. Since much is known of PA103 O-antigen genetics and because the sugars at the reducing termini of the O7 (strain 1244) and O11 (strain PA103) are identical (β-
N
-acetyl fucosamine), we utilized PA103 and strains that express lipopolysaccharide (LPS) with a truncated O-antigen subunit to test our hypothesis. LPS from a strain mutated in the
wbjE
gene produced an incomplete O subunit, consisting only of the monosaccharide at the reducing end (β-
d
-
N
-acetyl fucosamine), indicating that this moiety contained substrate recognition elements for WaaL. Expression of
pilAO
1244
in PA103
wbjE
::
aacC1
, followed by Western blotting of extracts of these cells, indicated that pilin produced has been modified by the addition of material consistent with a single
N
-acetyl fucosamine. This was confirmed by analyzing endopeptidase-treated pilin by mass spectrometry. These data suggest that the pilin glycosylation substrate recognition features lie within the reducing-end moiety of the O repeat and that structures of the remaining sugars are irrelevant.
Translation Inhibition of the
Salmonella fliC
Gene by the
fliC
5′ Untranslated Region,
fliC
Coding Sequences, and FlgM
Authors: Rosu Valentina , Chevance Fabienne F. V. , Karlinsey Joyce E. , Hirano Takanori , Hughes Kelly T. 
Published: June 2006

ABSTRACT

The 5′-untranslated region (5′UTR) of the
fliC
flagellin gene of
Salmonella
contains sequences critical for efficient
fliC
mRNA translation coupled to assembly. In a previous study we used targeted mutagenesis of the 5′ end of the
fliC
gene to isolate single base changes defective in
fliC
gene translation. This identified a predicted stem-loop structure, SL2, as an effector of normal
fliC
mRNA translation. A single base change (−38C:U) in the
fliC
5′UTR resulted in a mutant that is defective in
fliC
mRNA translation and was chosen for this study. Motile (Mot
+
) revertants of the −38C:T mutant were isolated and characterized, yielding several unexpected results. Second-site suppressors that restored
fliC
translation and motility included mutations that disrupt a RNA duplex stem formed between RNA sequences in the
fliC
5′UTR SL2 region (including a precise deletion of SL2) and bases early within the
fliC
-coding region. A stop codon mutation at position 80 of
flgM
also suppressed the −38C:T motility defect, while
flgM
mutants defective in anti-σ
28
activity had no effect on
fliC
translation. One remarkable mutation in the
fliC
5′UTR (−15G:A) results in a translation defect by itself but, in combination with the −38C:U mutation, restores normal translation. These results suggests signals intrinsic to the
fliC
mRNA that have both positive and negative effects on
fliC
translation involving both RNA structure and interacting proteins.