The serotype-specific glucose side chain of rhamnose-glucose polysaccharides is essential for adsorption of bacteriophage M102 to Streptococcus mutans

Bacteriophage M102 is a virulent siphophage that propagates in some serotype c Streptococcus mutans strains, but not in S. mutans of serotype e, f or k. The serotype of S. mutans is determined by the glucose side chain of rhamnose-glucose polysaccharide (RGP). Because the first step in the bacteriophage infection process is adsorption of the phage, it was investigated whether the serotype specificity of phage M102 was determined by adsorption. M102 adsorbed to all tested serotype c strains, but not to strains of different serotypes. Streptococcus mutans serotype c mutants defective in the synthesis of the glucose side chain of RGP failed to adsorb phage M102. These results suggest that the glucose side chain of RGP acts as a receptor for phage M10

Functional analysis of the Bacillus subtilis cysK and cysJI genes

The function of the Bacillus subtilis cysK and cysJI (previously designated yvgQR) genes, expected to be involved in the assimilatory sulfate reduction pathway, was investigated. A B. subtilis mutant with a deletion in the cysJI genes was unable to use sulfate or sulfite as sulfur source, which confirmed that these genes encode sulfite reductase. A mutant with a transposon insertion in the cysK gene, whose deduced protein sequence showed similarity to cysteine synthases, grew poorly on sulfate and butanesulfonate. A strain in which cysK and yrhA, a cysK paralog, were inactivated was unable to grow with sulfate. Whereas expression of the cysJI genes was induced by sulfate, expression of cysK was repressed both by sulfate and by cystein

GENETICS AND BIOCHEMISTRY OF DEHALOGENATING ENZYMES

Microorganisms that can utilize halogenated compounds as a growth substrate generally produce enzymes whose function is carbon-halogen bond cleavage. Based on substrate range, reaction type and gene sequences, the dehalogenating enzymes can be classified in different groups, including hydrolytic dehalogenases, glutathione transferases, monooxygenases and hydratases. X-ray crystallographic and biochemical studies have provided detailed mechanistic insight into the action of haloalkane dehalogenase. The essential features are nucleophilic substitution of the halogen by a carboxylate group and the presence of a distinct halogen binding site, formed by tryptophan residues. This review summaries current knowledge on a variety of other dehalogenating enzymes and indicates the existence of a widespread and diverse microbial potential for dechlorination of natural and xenobiotic halogenated compounds

Quantitation of Guggenheimella bovis and treponemes in bovine tissues related to digital dermatitis

Digital dermatitis is an inflammation of uncertain aetiology in the skin of the foot of cattle. In 2005, a novel microorganism, Guggenheimella bovis, was isolated from the advancing front of digital dermatitis lesions, suggesting a possible role in pathogenesis. In the present study, tissue samples of 20 affected cows were examined by quantitative PCR for G. bovis, treponemes and the total eubacterial load. High numbers of eubacteria and treponemes were found in most lesions, whereas only a few lesions contained Guggenheimella, and only at low concentrations. The results argue against the relevance of G. bovis in the aetiology of digital dermatitis in cattle, but are consistent with a role for treponeme

Quantitative detection of Porphyromonas gingivalis fimA genotypes in dental plaque

We developed quantitative fimA genotype assays and applied them in a pilot study investigating the fimbrial genotype distribution of Porphyromonas gingivalis in European subjects with or without chronic periodontitis. P. gingivalis was found in 71% and 9% of the samples from patients and healthy subjects, respectively. Enumeration of total P. gingivalis cell numbers by polymerase chain reaction and immunofluorescence showed excellent correspondence (r=0.964). 73% of positive samples contained multiple fimA genotypes, but generally one genotype predominated by one to three orders of magnitude. Genotype II predominated in 60% of the samples. Genotype IV occurred with similar prevalence (73%) as genotype II but predominated in only 20% of the samples. Genotypes I, III and V were of much lower prevalence and cell densities of the latter two remained sparse. Our results suggest marked differences among the fimA genotypes' ability to colonize host sites with high cell number

High-salinity growth conditions promote tat-independent secretion of tat substrates in Bacillus subtilis

The Gram-positive bacterium Bacillus subtilis contains two Tat translocases, which can facilitate transport of folded proteins across the plasma membrane. Previous research has shown that Tat-dependent protein secretion in B. subtilis is a highly selective process and that heterologous proteins, such as the green fluorescent protein (GFP), are poor Tat substrates in this organism. Nevertheless, when expressed in Escherichia coli, both B. subtilis Tat translocases facilitated exclusively Tat-dependent export of folded GFP when the twin-arginine (RR) signal peptides of the E. coli AmiA, DmsA, or MdoD proteins were attached. Therefore, the present studies were aimed at determining whether the same RR signal peptide-GFP precursors would also be exported Tat dependently in B. subtilis. In addition, we investigated the secretion of GFP fused to the full-length YwbN protein, a strict Tat substrate in B. subtilis. Several investigated GFP fusion proteins were indeed secreted in B. subtilis, but this secretion was shown to be completely Tat independent. At high-salinity growth conditions, the Tat-independent secretion of GFP as directed by the RR signal peptides from the E. coli AmiA, DmsA, or MdoD proteins was significantly enhanced, and this effect was strongest in strains lacking the TatAy-TatCy translocase. This implies that high environmental salinity has a negative influence on the avoidance of Tat-independent secretion of AmiA-GFP, DmsA-GFP, and MdoD-GFP. We conclude that as-yet-unidentified control mechanisms reject the investigated GFP fusion proteins for translocation by the B. subtilis Tat machinery and, at the same time, set limits to their Tat-independent secretion, presumably via the Sec pathway

Protocol for the CUPIDO trials; multicenter randomized controlled trials to assess the value of combining prolapse surgery and incontinence surgery in patients with genital prolapse and evident stress incontinence (CUPIDO I) and in patients with genital prolapse and occult stress incontinence (CUPIDO II)

Background: About 40% of all patients with genital prolapse report stress-incontinence. In about half of the 60% patients that do not report stress-incontinence, occult urinary stress-incontinence can be detected. In these patients stress-incontinence is masked due to kinking or compression of the urethra by the prolapse. In case surgical correction is indicated there are two strategies to manage patients with combined prolapse and (occult) stress incontinence. This strategy is either (i) a combination of prolapse surgery and stress-incontinence surgery or (ii) to correct the prolapse first and evaluate afterwards whether additional stress-incontinence surgery is indicated. The advantage of combining prolapse and stress-incontinence surgery is that only few patients report stress-incontinence following such combination. However, this combination has been associated with an increased risk on complications, of which the development of obstructive micturition symptoms, overactive bladder symptoms and bladder retention are the most important ones. Furthermore, combining two procedures may be unnecessary as performing only prolapse surgery may cure stress-incontinence In the randomized CUPIDO trials both strategies are compared in patients with prolapse and evident stress incontinence (CUPIDO I trial) and in patients with prolapse and occult stress incontinence (CUPIDO II trial). Methods/Design: The CUPIDO trials are two multicenter randomized controlled trials in which women with stress urinary incontinence (SUI) or occult stress urinary incontinence (OSUI) are randomized to prolapse surgery combined with anti incontinence surgery (concomitant surgery) or to prolapse surgery only. Patients with at least stage 2 POP are eligible, women with evident SUI are randomized in CUPIDO I. Patients without SUI are eligible for CUPIDO II and will have urodynamic evaluation or a standardized redression test. Women with OSUI are randomized, women without OSUI are followed up but not randomized. The primary outcome measure is absence of SUI twelve months after surgery. Furthermore, economic evaluations are conducted, and the effectiveness of urodynamic investigation is evaluated against a non-invasive way to determine SUI in women with POP. A total of 450 women will be included in the study

Becoming and staying physically active in adolescents with cerebral palsy: protocol of a qualitative study of facilitators and barriers to physical activity

<p>Abstract</p> <p>Background</p> <p>Adolescents with cerebral palsy (CP) show a reduced physical activity (PA). Currently there are no interventions for adolescents with CP in this critical life phase that optimise and maintain the individuals' physical activity in the long term. To develop such a program it is important to fully understand the factors that influence physical activity behaviours in adolescents with CP. The aim of this study is to explore what makes it easy or hard for adolescents with CP to be and to become physically active.</p> <p>Methods/Design</p> <p>A qualitative research method is chosen to allow adolescents to voice their own opinion. Because we will investigate the lived experiences this study has a phenomenological approach. Thirty ambulatory and non-ambulatory adolescents (aged 10-18 years) with CP, classified as level I to IV on the Gross Motor Function Classification System and 30 parents of adolescents with CP will be invited to participate in one of the 6 focus groups or an individual interview. Therapists from all Children's Treatment Centres in Ontario, Canada, will be asked to fill in a survey. Focus groups will be audio- and videotaped and will approximately take 1.5 hours. The focus groups will be conducted by a facilitator and an assistant. In preparation of the focus groups, participants will fill in a demographic form with additional questions on physical activity. The information gathered from these questions and recent research on barriers and facilitators to physical activity will be used as a starting point for the content of the focus groups. Recordings of the focus groups will be transcribed and a content analysis approach will be used to code the transcripts. A preliminary summary of the coded data will be shared with the participants before themes will be refined.</p> <p>Discussion</p> <p>This study will help us gain insight and understanding of the participants' experiences and perspectives in PA, which can be of great importance when planning programs aimed at helping them to stay or to become physically active.</p

Sequencing of neuroblastoma identifies chromothripsis and defects in neuritogenesis genes

Neuroblastoma is a childhood tumour of the peripheral sympathetic nervous system. The pathogenesis has for a long time been quite enigmatic, as only very few gene defects were identified in this often lethal tumour. Frequently detected gene alterations are limited to MYCN amplification (20%) and ALK activations (7%). Here we present a whole-genome sequence analysis of 87 neuroblastoma of all stages. Few recurrent amino-acid-changing mutations were found. In contrast, analysis of structural defects identified a local shredding of chromosomes, known as chromothripsis, in 18% of high-stage neuroblastoma. These tumours are associated with a poor outcome. Structural alterations recurrently affected ODZ3, PTPRD and CSMD1, which are involved in neuronal growth cone stabilization. In addition, ATRX, TIAM1 and a series of regulators of the Rac/Rho pathway were mutated, further implicating defects in neuritogenesis in neuroblastoma. Most tumours with defects in these genes were aggressive high-stage neuroblastomas, but did not carry MYCN amplifications. The genomic landscape of neuroblastoma therefore reveals two novel molecular defects, chromothripsis and neuritogenesis gene alterations, which frequently occur in high-risk tumours

Use of mental health services among disaster survivors: predisposing factors

<p>Abstract</p> <p>Background</p> <p>Given the high prevalence of mental health problems after disasters it is important to study health services utilization. This study examines predictors for mental health services (MHS) utilization among survivors of a man-made disaster in the Netherlands (May 2000).</p> <p>Methods</p> <p>Electronic records of survivors (n = 339; over 18 years and older) registered in a mental health service (MHS) were linked with general practice based electronic medical records (EMRs) of survivors and data obtained in surveys. EMR data were available from 16 months pre-disaster until 3 years post-disaster. Symptoms and diagnoses in the EMRs were coded according to the International Classification of Primary Care (ICPC). Surveys were carried out 2–3 weeks and 18 months post-disaster, and included validated questionnaires on psychological distress, post-traumatic stress reactions and social functioning. Demographic and disaster-related variables were available. Predisposing factors for MHS utilization 0–18 months and 18–36 months post-disaster were examined using multiple logistic regression models.</p> <p>Results</p> <p>In multiple logistic models, adjusting for demographic and disaster related variables, MHS utilization was predicted by demographic variables (young age, immigrant, public health insurance, unemployment), disaster-related exposure (relocation and injuries), self-reported psychological problems and pre- and post-disaster physician diagnosed health problems (chronic diseases, musculoskeletal problems). After controlling for all health variables, disaster intrusions and avoidance reactions (OR:2.86; CI:1.48–5.53), hostility (OR:2.04; CI:1.28–3.25), pre-disaster chronic diseases (OR:1.82; CI:1.25–2.65), injuries as a result of the disaster (OR:1.80;CI:1.13–2.86), social functioning problems (OR:1.61;CI:1.05–2.44) and younger age (OR:0.98;CI:0.96–0.99) predicted MHS utilization within 18 months post-disaster. Furthermore, disaster intrusions and avoidance reactions (OR:2.29;CI:1.04–5.07) and hostility (OR:3.77;CI:1.51–9.40) predicted MHS utilization following 18 months post-disaster.</p> <p>Conclusion</p> <p>This study showed that several demographic and disaster-related variables and self-reported and physician diagnosed health problems predicted post-disaster MHS-use. The most important factors to predict post-disaster MHS utilization were disaster intrusions and avoidance reactions and symptoms of hostility (which can be identified as symptoms of PTSD) and pre-disaster chronic diseases.</p