Variable cartilage degradation in mice with diet-induced metabolic dysfunction: food for thought.

OBJECTIVE: Human cohort studies have demonstrated a role for systemic metabolic dysfunction in osteoarthritis (OA) pathogenesis in obese patients. To explore the mechanisms underlying this metabolic phenotype of OA, we examined cartilage degradation in the knees of mice from different genetic backgrounds in which a metabolic phenotype was established by various dietary approaches. DESIGN: Wild-type C57BL/6J mice and genetically modified mice (hCRP, LDLr-/-. Leiden and ApoE*3Leiden.CETP mice) based on C57BL/6J background were used to investigate the contribution of inflammation and altered lipoprotein handling on diet-induced cartilage degradation. High-caloric diets of different macronutrient composition (i.e., high-carbohydrate or high-fat) were given in regimens of varying duration to induce a metabolic phenotype with aggravated cartilage degradation relative to controls. RESULTS: Metabolic phenotypes were confirmed in all studies as mice developed obesity, hypercholesteremia, glucose intolerance and/or insulin resistance. Aggravated cartilage degradation was only observed in two out of the twelve experimental setups, specifically in long-term studies in male hCRP and female ApoE*3Leiden.CETP mice. C57BL/6J and LDLr-/-. Leiden mice did not develop HFD-induced OA under the conditions studied. Osteophyte formation and synovitis scores showed variable results between studies, but also between strains and gender. CONCLUSIONS: Long-term feeding of high-caloric diets consistently induced a metabolic phenotype in various C57BL/6J (-based) mouse strains. In contrast, the induction of articular cartilage degradation proved variable, which suggests that an additional trigger might be necessary to accelerate diet-induced OA progression. Gender and genetic modifications that result in a humanized pro-inflammatory state (human CRP) or lipoprotein metabolism (human-E3L.CETP) were identified as important contributing factors.

The working alliance, beliefs about the supervisor, and counseling self-efficacy: Applying the relational efficacy model to counselor supervision.

There is need for closer examination of how counselors' efficacy beliefs develop and function within actual counseling or supervisory relationships. We adapted Lent and Lopez's (2002) model of relational efficacy beliefs to the context of counseling supervision, examining possible linkages of counselors' self-efficacy to beliefs about how their supervisor perceives their (counselors') efficacy (termed relation-inferred self-efficacy [RISE]), beliefs about the supervisor's efficacy (other-efficacy), and perceptions of the supervisory working alliance. Two hundred forty graduate student counselors completed the relational efficacy belief measures in relation to a particularly challenging client on their caseloads. Path analysis findings suggested that the hypothesized model provided good fit to the data. In particular, counselors' RISE beliefs regarding their supervisors were well-predicted by the supervisory working alliance, other-efficacy beliefs about the supervisor, amount of clinical experience, and perceived client distress level. RISE beliefs (along with amount of clinical experience), in turn, predicted counselors' self-efficacy. In addition, the strength of the relationship between RISE and counselor self-efficacy was moderated by other-efficacy, suggesting that supervisors' clinical credibility, from the perspective of their supervisees, plays an important role in their ability to promote the efficacy of their supervisees. (PsycINFO Database Record

Development of Multiwell-Plate Methods Using Pure Cultures of Methanogens To Identify New Inhibitors for Suppressing Ruminant Methane Emissions.

Hydrogenotrophic methanogens typically require strictly anaerobic culturing conditions in glass tubes with overpressures of H2 and CO2 that are both time-consuming and costly. To increase the throughput for screening chemical compound libraries, 96-well microtiter plate methods for the growth of a marine (environmental) methanogen Methanococcus maripaludis strain S2 and the rumen methanogen Methanobrevibacter species AbM4 were developed. A number of key parameters (inoculum size, reducing agents for medium preparation, assay duration, inhibitor solvents, and culture volume) were optimized to achieve robust and reproducible growth in a high-throughput microtiter plate format. The method was validated using published methanogen inhibitors and statistically assessed for sensitivity and reproducibility. The Sigma-Aldrich LOPAC library containing 1,280 pharmacologically active compounds and an in-house natural product library (120 compounds) were screened against M. maripaludis as a proof of utility. This screen identified a number of bioactive compounds, and MIC values were confirmed for some of them against M. maripaludis and M. AbM4. The developed method provides a significant increase in throughput for screening compound libraries and can now be used to screen larger compound libraries to discover novel methanogen-specific inhibitors for the mitigation of ruminant methane emissions.IMPORTANCE Methane emissions from ruminants are a significant contributor to global greenhouse gas emissions, and new technologies are required to control emissions in the agriculture technology (agritech) sector. The discovery of small-molecule inhibitors of methanogens using high-throughput phenotypic (growth) screening against compound libraries (synthetic and natural products) is an attractive avenue. However, phenotypic inhibitor screening is currently hindered by our inability to grow methanogens in a high-throughput format. We have developed, optimized, and validated a high-throughput 96-well microtiter plate assay for growing environmental and rumen methanogens. Using this platform, we identified several new inhibitors of methanogen growth, demonstrating the utility of this approach to fast track the development of methanogen-specific inhibitors for controlling ruminant methane emissions.

Inflammasome signaling affects anxiety- and depressive-like behavior and gut microbiome composition.

The inflammasome is hypothesized to be a key mediator of the response to physiological and psychological stressors, and its dysregulation may be implicated in major depressive disorder. Inflammasome activation causes the maturation of caspase-1 and activation of interleukin (IL)-1ß and IL-18, two proinflammatory cytokines involved in neuroimmunomodulation, neuroinflammation and neurodegeneration. In this study, C57BL/6 mice with genetic deficiency or pharmacological inhibition of caspase-1 were screened for anxiety- and depressive-like behaviors, and locomotion at baseline and after chronic stress. We found that genetic deficiency of caspase-1 decreased depressive- and anxiety-like behaviors, and conversely increased locomotor activity and skills. Caspase-1 deficiency also prevented the exacerbation of depressive-like behaviors following chronic stress. Furthermore, pharmacological caspase-1 antagonism with minocycline ameliorated stress-induced depressive-like behavior in wild-type mice. Interestingly, chronic stress or pharmacological inhibition of caspase-1 per se altered the fecal microbiome in a very similar manner. When stressed mice were treated with minocycline, the observed gut microbiota changes included increase in relative abundance of Akkermansia spp. and Blautia spp., which are compatible with beneficial effects of attenuated inflammation and rebalance of gut microbiota, respectively, and the increment in Lachnospiracea abundance was consistent with microbiota changes of caspase-1 deficiency. Our results suggest that the protective effect of caspase-1 inhibition involves the modulation of the relationship between stress and gut microbiota composition, and establishes the basis for a gut microbiota-inflammasome-brain axis, whereby the gut microbiota via inflammasome signaling modulate pathways that will alter brain function, and affect depressive- and anxiety-like behaviors. Our data also suggest that further elucidation of the gut microbiota-inflammasome-brain axis may offer novel therapeutic targets for psychiatric disorders.

Fibromyalgia and bipolar disorder: extent of comorbidity and therapeutic implications.

Fibromyalgia (FM) is a syndrome that affects muscles and soft tissues. Presenting symptoms include chronic muscle pain, fatigue, sleep problems and psychological symptoms, including depression and anxiety. There exists strong evidence of a comorbidity between FM and Bipolar Disorder (BD). In this study, papers from 2006 to February 2016 that examined the comorbidity and etiological similarities of FM and BD were reviewed, as well as the therapeutic implications of these findings. The reviewed articles showed that an adequate psychiatric screening for BD is recommended in FM patients with depressive symptoms, in order to decrease administration of antidepressants for BD, due to the lack of proven efficacy, and to limit antidepressant-induced mania. Alternative therapies, such as agomelatine, memantine and psychotherapic treatment should be considered.

Rewards of parenting children and adolescents with spinal cord injuries.

STUDY DESIGN: Mixed-method study. OBJECTIVES: Describe caregiver perspectives on the rewards of parenting youth with spinal cord injury (SCI) and explore the relationships between rewards and child/caregiver demographic characteristics and child psychosocial outcomes. SETTING: Data collection occurred at three pediatric specialty hospitals within a single hospital system in the United States. METHODS: Self-identified primary caregivers (n=178) of children aged 1-18 years answered the question: 'What has been most rewarding in parenting a child with SCI'? and completed a questionnaire about their child's health-related quality of life (HRQOL). Participants aged 7-18 years (n=134) also completed tools assessing their community participation, anxiety, depression and HRQOL. RESULTS: Four reward themes emerged: Enhanced Resilience (for example, resilience in my child, self and family), Caregiver-Child Relationship, Connecting with Others, and Learning. Caregivers of children with lower self-reported school and overall psychosocial HRQOL were more likely to report Enhanced Resilience in their child. Caregivers whose children had fewer depressive symptoms, lower levels of participation and who were older at injury and interview felt rewarded by an enhanced Caregiver-Child Relationship. Caregivers of children with a broader context of participation and higher school and psychosocial HRQOL reported Connecting with Others. Finally, unemployed caregivers and those with less education were more likely to report Learning. CONCLUSIONS: Caregivers reported a variety of rewards from parenting their children with SCI, and several relationships emerged between rewards and demographics and child psychosocial outcomes. Future research should further examine the positive experiences of caregivers and whether focusing on strengths might yield better long-term outcomes for children with SCI.

Screening for Functional Cognition in Postacute Care and the Improving Medicare Post-Acute Care Transformation (IMPACT) Act of 2014.

Occupational therapists have a long history of assessing functional cognition, defined as the ability to use and integrate thinking and performance skills to accomplish complex everyday activities. In response to passage of the Improving Medicare Post-Acute Care Transformation (IMPACT) Act of 2014 (Pub. L. 113-185), the American Occupational Therapy Association has been advocating that the Centers for Medicare and Medicaid Services consider functional cognition for inclusion in routine patient assessment in postacute care settings, with important implications for occupational therapy. These efforts have the potential to increase referrals to occupational therapy, emphasize the importance of addressing functional cognition in occupational therapy practice, and support the value of occupational therapy in achieving optimal postacute care outcomes.

Surgical removal of inflamed epididymal white adipose tissue attenuates the development of non-alcoholic steatohepatitis in obesity.

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) is strongly associated with abdominal obesity. Growing evidence suggests that inflammation in specific depots of white adipose tissue (WAT) has a key role in NAFLD progression, but experimental evidence for a causal role of WAT is lacking. METHODS: A time-course study in C57BL/6J mice was performed to establish which WAT depot is most susceptible to develop inflammation during high-fat diet (HFD)-induced obesity. Crown-like structures (CLS) were quantified in epididymal (eWAT), mesenteric (mWAT) and inguinal/subcutaneous (iWAT) WAT. The contribution of inflamed WAT to NAFLD progression was investigated by surgical removal of a selected WAT depot and compared with sham surgery. Plasma markers were analyzed by enzyme-linked immunosorbent assay (cytokines/adipokines) and lipidomics (lipids). RESULTS: In eWAT, CLS were formed already after 12 weeks of HFD, which coincided with maximal adipocyte size and fat depot mass, and preceded establishment of non-alcoholic steatohepatitis (NASH). By contrast, the number of CLS were low in mWAT and iWAT. Removal of inflamed eWAT after 12 weeks (eWATx group), followed by another 12 weeks of HFD feeding, resulted in significantly reduced NASH in eWATx. Inflammatory cell aggregates (-40%; P<0.05) and inflammatory genes (e.g., TNFα, -37%; P<0.05) were attenuated in livers of eWATx mice, whereas steatosis was not affected. Concomitantly, plasma concentrations of circulating proinflammatory mediators, viz. leptin and specific saturated and monounsaturated fatty acids, were also reduced in the eWATx group. CONCLUSIONS: Intervention in NAFLD progression by removal of inflamed eWAT attenuates the development of NASH and reduces plasma levels of specific inflammatory mediators (cytokines and lipids). These data support the hypothesis that eWAT is causally involved in the pathogenesis of NASH.

Intervention with a caspase-1 inhibitor reduces obesity-associated hyperinsulinemia, non-alcoholic steatohepatitis and hepatic fibrosis in LDLR-/-.Leiden mice.

BACKGROUND/OBJECTIVES: Non-alcoholic steatohepatitis (NASH) is a serious liver condition, closely associated with obesity and insulin resistance. Recent studies have suggested an important role for inflammasome/caspase-1 in the development of NASH, but the potential therapeutic value of caspase-1 inhibition remains unclear. Therefore, we aimed to investigate the effects of caspase-1 inhibition in the ongoing disease process, to mimic the clinical setting. SUBJECTS/METHODS: To investigate effects of caspase-1 inhibition under therapeutic conditions, male LDLR-/-.Leiden mice were fed a high-fat diet (HFD) for 9 weeks to induce a pre-diabetic state before start of treatment. Mice were then continued on HFD for another 12 weeks, without (HFD) or with (HFD-YVAD) treatment with the caspase-1 inhibitor Ac-YVAD-cmk (40 mg kg(-1) per day). RESULTS: Nine weeks of HFD feeding resulted in an obese phenotype, with obesity-associated hypertriglyceridemia, hypercholesterolemia, hyperglycemia and hyperinsulinemia. Treatment with Ac-YVAD-cmk did not affect further body weight gain or dyslipidemia, but did attenuate further progression of insulin resistance. Histopathological analysis of livers clearly demonstrated prevention of NASH development in HFD-YVAD mice: livers were less steatotic and neutrophil infiltration was strongly reduced. In addition, caspase-1 inhibition had a profound effect on hepatic fibrosis, as assessed by histological quantification of collagen staining and gene expression analysis of fibrosis-associated genes Col1a1, Acta2 and Tnfa. CONCLUSIONS: Intervention with a caspase-1 inhibitor attenuated the development of NASH, liver fibrosis and insulin resistance. Our data support the importance of inflammasome/caspase-1 in the development of NASH and demonstrate that therapeutic intervention in the already ongoing disease process is feasible.

Microbial biofilms associated with intravascular catheter-related bloodstream infections in adult intensive care patients.

Catheter-related bloodstream infection (CRBSI) is one of the most serious complications in hospitalised patients, leading to increased hospitalisation, intensive care admissions, extensive antibiotic treatment and mortality. A greater understanding of these bacterial infections is needed to improve the prevention and the management of CRBSIs. We describe here the systematic culture-independent evaluation of intravascular catheter (IVC) bacteriology. Twelve IVCs (6 central venous catheters and 6 arterial catheters) were collected from 6 patients. By using traditional culture methods, 3 patients were diagnosed with catheter colonisation including 1 patient who also had CRBSI, and 3 had no colonisation. From a total of 839,539 high-quality sequence reads from high-throughput sequencing, 8 microbial phyla and 76 diverse microbial genera were detected. All IVCs examined in this study were colonised with complex microbial communities including "non-colonised IVCs," as defined using traditional culture methods. Two main community types were observed: Enterobacteriaceae spp., dominant in patients without colonisation or CRBSI; and Staphylococcus spp., dominant in patients with colonisation and CRBSI. More diverse pathogens and a higher microbial diversity were present in patients with IVC colonisation and CRBSI. Community composition did not appear to be affected by patients' antibiotic treatment or IVC type. Characterisation of these communities is the first step in elucidating roles of these pathogens in disease progression, and to ultimately facilitate the improved prevention, refined diagnosis and management of CRBSI.

Is vitamin E an anti-allergic compound?

Vitamin E is found in eight forms in nature which include four tocopherols (alpha, beta, gamma and delta) and four tocotrianols (alpha, beta, gamma and delta). The classic effect of vitamin E is to reduce and prevent oxygen damage to the tissue and is useful for the treatment of pain, inflammation and allergic reactions. In addition to antioxidant activity, vitamin E also has a number of different and related functions. It protects against cancer, improves immune response, lowers the incidence of infectious diseases, cardiovascular diseases and is protective in allergy and asthma risk, and other disorders. Vitamin E increases n-6 polyunsaturated fatty acid (PUFA) and decreases n-3 PUFA, an effect that diminishes asthma and allergic diseases. Moreover, vitamin E regulates vascular cell adhesion molecule-1 (VCAM-1)-dependent leukocyte migration through its oxidant and non-antioxidant effect. Furthermore, vitamin E modulates the endothelial function by altering VCAM-1-induced oxidative activation of endothelial cell PKCα. However, vitamin E is not consistently associated with asthma and/or allergy, and in some cases there are conflicting results on allergy and inflammatory diseases. The association of vitamin E and allergy appears to be very complex, and further study needs to clarify this dilemma.

Microbial diversity on intravascular catheters from paediatric patients.

Microorganisms play important roles in intravascular catheter (IVC)-related infections, which are the most serious complications in children with IVCs, leading to increased hospitalisation, intensive care admissions, extensive antibiotic treatment and mortality. A greater understanding of bacterial communities is needed in order to improve the management of infections. We describe here the systematic culture-independent evaluation of IVC bacteriology in IVC biofilms. Twenty-four IVC samples (six peripherally inserted central catheters, eight central venous catheters and ten arterial catheters) were collected from 24 paediatric patients aged 0 to 14 years old. Barcoded amplicon libraries produced from genes coding 16S rRNA and roll-plate culture methods were used to determine the microbial composition of these samples. From a total of 1,043,406 high-quality sequence reads, eight microbial phyla and 136 diverse microbial genera were detected, separated into 12,224 operational taxonomic units (OTUs). Three phyla (Actinobacteria, Firmicutes and Proteobacteria) predominate the microorganism on the IVC surfaces, with Firmicutes representing nearly half of the OTUs found. Among the Firmicutes, Staphylococcus (15.0% of 16S rRNA reads), Streptococcus (9.6%) and Bacillus (6.1%) were the most common. Community composition did not appear to be affected by patients' age, gender, antibiotic treatment or IVC type. Differences in IVC microbiota were more likely associated with events arising from catheter dwell time, rather than the type of IVC used.

Acute gastrointestinal illness following a prolonged community-wide water emergency.

The drinking water infrastructure in the United States is ageing; extreme weather events place additional stress on water systems that can lead to interruptions in the delivery of safe drinking water. We investigated the association between household exposures to water service problems and acute gastrointestinal illness (AGI) and acute respiratory illness (ARI) in Alabama communities that experienced a freeze-related community-wide water emergency. Following the water emergency, investigators conducted a household survey. Logistic regression models were used to estimate adjusted prevalence ratios (aPR) and 95% confidence intervals (CI) for self-reported AGI and ARI by water exposures. AGI was higher in households that lost water service for ⩾7 days (aPR 2·4, 95% CI 1·1-5·2) and experienced low water pressure for ⩾7 days (aPR 3·6, 95% CI 1·4-9·0) compared to households that experienced normal service and pressure; prevalence of AGI increased with increasing duration of water service interruptions. Investments in the ageing drinking water infrastructure are needed to prevent future low-pressure events and to maintain uninterrupted access to the fundamental public health protection provided by safe water supplies. Households and communities need to increase their awareness of and preparedness for water emergencies to mitigate adverse health impacts.

Performance-based testing in mild stroke: identification of unmet opportunity for occupational therapy.

Age at first stroke is decreasing, and most strokes are mild to moderate in severity. Executive function (EF) deficits are increasingly recognized in the stroke population, but occupational therapists have not altered their evaluation methods to fully accommodate changing patient needs. We present a hierarchical performance-based testing (PBT) pathway using data to illustrate how PBT could identify patients with mild stroke-related EF deficits in need of occupational therapy intervention. Data suggest that a substantial number of patients with EF deficits after mild stroke could benefit from occupational therapy services.

Molecular investigation of bacterial communities on intravascular catheters: no longer just Staphylococcus.

Intravascular catheter-related bloodstream infections (IVC-BSIs) are associated with significant morbidity and mortality. Culture-independent molecular approaches can reveal and capture the composition of complex microbial communities, and are now being used to reveal "new" pathogens as well as the polymicrobial nature of some infections. Patients with concurrently sited arterial and central venous catheters who had clinically suspected IVC-BSIs, were examined by the high-throughput sequencing of microbial 16S rRNA. An average of 100 operational taxonomic units (OTUs, phylotypes) was observed on each IVC, indicating that IVCs were colonised by complex and diverse bacterial communities. Ralstonia (53 % of 16S rRNA sequences), Escherichia group (16 %), Propionibacterium (5 %), Staphylococcus (5 %), and Streptococcus (2 %) were the most abundant genera. There was no statistically significant difference in the bacterial communities examined from arterial and central venous catheters; from those with and without systemic antibiotic treatment; or from conventionally colonised and uncolonised IVCs. The genome of the predominant bacteria, R. pickettii AU12-08, was found to encode resistance to antimicrobial drugs of different classes. In addition, many encoded gene products are involved in quorum sensing and biofilm formation that would further contribute to increased antimicrobial drug resistance. Our results highlight the complex diversity of microbial ecosystems on vascular devices. High-throughput sequencing of 16S rRNA offers an insight into the pathogenesis of IVC-related infections, and opens up the scope for improving diagnosis and patient management.

Development of a phylogenetic microarray for comprehensive analysis of ruminal bacterial communities.

AIMS: The aim of the study was to develop a microarray dedicated to comprehensive analysis of the diverse rumen bacteria. METHODS AND RESULTS: All the 16S rRNA gene (rrs) sequences of rumen origin were retrieved from the RDP database, and operational taxonomic units (OTUs) were calculated at 97% sequence similarity. A total of 1666 OTU-specific probes were designed and synthesized on microarray slides (referred to as RumenBactArray) in a 6 × 5 k format with each probe being represented in triplicate. The specificity, sensitivity and linear range of detection were determined using pools of rrs clones of known sequences. The RumenBactArray detected as few as approx. 10(6) copies of a target and had a linear detection range of >4 orders of magnitude. The utility of the RumenBactArray was tested using fractionated rumen samples obtained from sheep fed two different diets. More than 300 different OTUs were detected across the four fractionated samples, and differences in bacterial communities were found between the two diets. CONCLUSIONS: This is the first phylochip dedicated to analysis of ruminal bacteria, and it enables comprehensive and semiquantitative analysis of ruminal bacteria. SIGNIFICANCE AND IMPACT OF THE STUDY: RumenBactArray can be a robust tool to comparatively analyse ruminal bacteria needed in nutritional studies of ruminant animals.

The advisory working alliance and research training: test of a relational efficacy model.

Relatively little research attention has been devoted to understanding the mechanisms through which the advising relationship functions as a medium for fostering doctoral students' development as researchers. Adapting Lent and Lopez's (2002) model of relational efficacy, we examined three types of efficacy beliefs (self-efficacy, other-efficacy, and relation-inferred self-efficacy) in relation to the advisory working alliance and the prediction of doctoral students' research interest and productivity. Gelso's (1993) concept of the research training environment was also included in model testing to capture a view of the advisory relationship as existing within a larger program training context. Participants were 274 doctoral students in a variety of academic fields. The results suggested that a slightly revised version of the hypothesized model produced good fit to the data. In particular, controlling for year in the graduate program, we found the advisory working alliance was linked to students' research self-efficacy indirectly via relation-inferred self-efficacy (i.e., students' beliefs about how their advisors viewed their research capabilities). Students' self-efficacy was, in turn, predictive of their interest in and productivity at research. We discuss the implications of these findings for future research and the practice of advising and research training.

[Olfactory function after transsphenoidal pituitary surgery]. / Fonction olfactive après chirurgie hypophysaire transsphénoidale.

Pituitary surgery remains mainly performed trough a transnasal, transseptal and transsphenoidal way. This surgical approach can damage intranasal structures and, in particular, may impede olfactory function. Our study investigates olfactory function in 67 patients undergoing this type of surgery before and 3 months after surgery. Mean olfactory scores were identical pre- and postoperatively. However, on an individual bases seven percent of the patients showed a clear decrease in olfactory function. In conclusion, transnasal, transseptal and transsphenoidal surgery is relativelv safe with regards to olfactory function

Molecular investigation of bacterial communities on the inner and outer surfaces of peripheral venous catheters.

Peripheral venous catheters (PVCs) are some of the most widely used medical devices in hospitals worldwide. PVC-related infections increase morbidity and treatment costs. The inner surfaces of PVCs are rarely examined for the population structure of bacteria, as it is generally believed that bacteria at this niche are similar to those on the external surface of PVCs. We primarily test this hypothesis and also study the effect of antibiotic treatment on bacterial communities from PVC surfaces. The inner and outer surfaces of PVCs from 15 patients were examined by 454 GS FLX Titanium 16S rRNA sequencing and the culture method. None of the PVCs were colonised according to the culture method and none of the patients had a bacteraemia. From a total of 127,536 high-quality sequence reads, 14 bacterial phyla and 268 diverse bacterial genera were detected. The number of operational taxonomic units for each sample was in the range of 86-157, even though 60 % of patients had received antibiotic treatment. Stenotrophomonas maltophilia was the predominant bacterial species in all the examined PVC samples. There were noticeable but not statistically significant differences between the inner and outer surfaces of PVCs in terms of the distribution of the taxonomic groups. In addition, the bacterial communities on PVCs from antibiotic-treated patients were significantly different from untreated patients. In conclusion, the surfaces of PVCs display complex bacterial communities. Although their significance has yet to be determined, these findings alter our perception of PVC-related infections.

Identification of metabolically active proteobacterial and archaeal communities in the rumen by DNA- and RNA-derived 16S rRNA gene.

AIMS: To gain new insights into the metabolic contribution of bacterial group in the rumen. METHODS AND RESULTS: Both DNA- and RNA-derived bacterial 16S ribosomal materials from bovine rumen contents were used as the template for bacterial community and analyse microbiota by three methods namely custom phylogenetic microarray, quantitative real-time PCR and denaturing gradient gel electrophoresis techniques. Bacterial analysis showed that genera affiliating with the Proteobacteria apparently made a greater metabolic contribution to rumen function than their population sizes indicated. Analysis of another rumen microbial group, the methanogens, using clone libraries for the expressed methyl coenzyme reductase subunit A (mcrA) revealed that an uncultivated methanogen clade contributes one-third of RNA-derived mcrA sequences based on a limited number of clones analysed. These uncultivated methanogen species were not observed in the mcrA gene library based on the DNA-derived sequences. CONCLUSIONS: The comparison of results obtained from DNA- and RNA-derived materials suggests that some of the Proteobacteria and novel methanogen species appeared to be low in abundance in the rumen maintained on grain-based diets might play a greater role in rumen metabolism. SIGNIFICANCE AND IMPACT OF THE STUDY: These studies provide the first report to compare high-throughput analysis of bacterial 16S rRNA genes from DNA- and RNA-derived materials to indicate differences that species make to community structure and metabolic activity.