Resilience to obesity among socioeconomically disadvantaged women : the READI study

Objective: This cross-sectional study aimed to identify sociodemographic and behavioural characteristics of ‘overweight-resilient’ women, that is, women who were in a healthy body weight range, despite living in socioeconomically disadvantaged neighbourhoods that place them at increased risk of obesity. The study also aimed to test a comprehensive theoretically derived model of the associations between intrapersonal, social and environmental factors and obesity among this target group.Participants: A total of 3235 women aged 18–45 years from 80 urban and rural neighbourhoods throughout Victoria, Australia, participated in the Resilience for Eating and Activity Despite Inequality study.Measurements: Women reported height, weight, sociodemographic characteristics, leisure-time physical activity, dietary behaviours and a range of theoretically derived cognitive, social and neighbourhood environmental characteristics hypothesized to influence obesity risk. A theoretical model predicting body mass index (BMI) was tested using structural equation models.Results: Women classified as ‘resilient’ to obesity tended to be younger, born overseas, more highly educated, unmarried and to have higher or undisclosed household incomes. They engaged in more leisure-time physical activity and consumed less fast foods and soft drinks than overweight/obese women. Neighbourhood characteristics, social characteristics and cognitive characteristics all contributed to explaining variation in BMI in the hypothesized directions.Conclusions: These results demonstrate several characteristics of women appearing ‘resilient’ to obesity, despite their increased risk conferred by residing in socioeconomically disadvantaged neighbourhoods. Acknowledging the cross-sectional study design, the results advance theoretical frameworks aimed at investigating obesity risk by providing evidence in support of a comprehensive model of direct and indirect effects on obesity of neighbourhood, as well as social, cognitive and behavioural characteristics

Biotechnological production and application of fructooligosaccharides

Currently, prebiotics are all carbohydrates of relatively short chain length. An important group is the fructooligosaccharides, which are a special kind of prebiotics associated to their selective stimulation of the activity of certain groups of colonic bacteria that have a positive and beneficial effect on intestinal microbiota, reducing incidence of gastrointestinal infections, respiratory and also possessing a recognized bifidogenic effect. Traditionally, these prebiotic compounds have been obtained through extraction processes from some plants, as well as through enzymatic hydrolysis of sucrose. However, different fermentative methods have also been proposed for the production of fructooligosaccharides, such as solid-state fermentation utilizing various agroindustrial by-products. By optimizing the culture parameters, fructooligosaccharides yields and productivity can be improved. The use of immobilized enzymes and cells has also been proposed as being an effective and economic method for large-scale production of fructooligosaccharides. This paper is an overview on the results of recent studies on fructooligosacharides biosynthesis, physicochemical properties, sources, biotechnological production and applications.The authors thank the National Council of Science and Technology of Mexico (CONACYT) for funding this study. D. A. Flores-Maltos thank the CONACYT for the financial support provided for her postgraduate studies in the Food Science and Technology Program, Universidad Autonoma de Coahuila, Mexico

Change in physical activity level and clinical outcomes in older adults with knee pain: a secondary analysis from a randomised controlled trial

BACKGROUND: Exercise interventions improve clinical outcomes of pain and function in adults with knee pain due to osteoarthritis and higher levels of physical activity are associated with lower severity of pain and higher levels of physical functioning in older adults with knee osteoarthritis in cross-sectional studies. However, to date no studies have investigated if change in physical activity level during exercise interventions can explain clinical outcomes of pain and function. This study aimed to investigate if change in physical activity during exercise interventions is associated with future pain and physical function in older adults with knee pain. METHODS: Secondary longitudinal data analyses of a three armed exercise intervention randomised controlled trial. Participants were adults with knee pain attributed to osteoarthritis, over the age of 45 years old (n = 514) from Primary Care Services in the Midlands and Northwest regions of England. Crude and adjusted associations between absolute change in physical activity from baseline to 3 months (measured by the self-report Physical Activity Scale for the Elderly (PASE)) and i) pain ii) physical function (Western Ontario and McMaster Universities Osteoarthritis Index) and iii) treatment response (OMERACT-OARSI responder criteria) at 3 and 6 months follow-up were investigated using linear and logistic regression. RESULTS: Change in physical activity level was not associated with future pain, function or treatment response outcomes in crude or adjusted models at 3 or 6 months (P > 0.05). A 10 point increase in PASE was not associated with pain β = - 0.01 (- 0.05, 0.02), physical function β = - 0.09 (- 0.19, 0.02) or likelihood (odds ratio) of treatment response 1.02 (0.99, 1.04) at 3 months adjusting for sociodemographics, clinical covariates and the trial intervention arm. Findings were similar for 6 month outcome models. CONCLUSIONS: Change in physical activity did not explain future clinical outcomes of pain and function in this study. Other factors may be responsible for clinical improvements following exercise interventions. However, the PASE may not be sufficiently responsive to measure change in physical activity level. We also recommend further investigation into the responsiveness of commonly used physical activity measures. TRIAL REGISTRATION: ( ISRCTN93634563 ). Registered 29th September 2011

Gut microbiota functions: metabolism of nutrients and other food components

The diverse microbial community that inhabits the human gut has an extensive metabolic repertoire that is distinct from, but complements the activity of mammalian enzymes in the liver and gut mucosa and includes functions essential for host digestion. As such, the gut microbiota is a key factor in shaping the biochemical profile of the diet and, therefore, its impact on host health and disease. The important role that the gut microbiota appears to play in human metabolism and health has stimulated research into the identification of specific microorganisms involved in different processes, and the elucidation of metabolic pathways, particularly those associated with metabolism of dietary components and some host-generated substances. In the first part of the review, we discuss the main gut microorganisms, particularly bacteria, and microbial pathways associated with the metabolism of dietary carbohydrates (to short chain fatty acids and gases), proteins, plant polyphenols, bile acids, and vitamins. The second part of the review focuses on the methodologies, existing and novel, that can be employed to explore gut microbial pathways of metabolism. These include mathematical models, omics techniques, isolated microbes, and enzyme assays

Utility of In Vivo Transcription Profiling for Identifying Pseudomonas aeruginosa Genes Needed for Gastrointestinal Colonization and Dissemination

Microarray analysis of Pseudomonas aeruginosa mRNA transcripts expressed in vivo during animal infection has not been previously used to investigate potential virulence factors needed in this setting. We compared mRNA expression in bacterial cells recovered from the gastrointestinal (GI) tracts of P. aeruginosa-colonized mice to that of P. aeruginosa in the drinking water used to colonize the mice. Genes associated with biofilm formation and type III secretion (T3SS) had markedly increased expression in the GI tract. A non-redundant transposon library in P. aeruginosa strain PA14 was used to test mutants in genes identified as having increased transcription during in vivo colonization. All of the Tn-library mutants in biofilm-associated genes had an attenuated ability to form biofilms in vitro, but there were no significant differences in GI colonization and dissemination between these mutants and WT P. aeruginosa PA14. To evaluate T3SS factors, we tested GI colonization and neutropenia-induced dissemination of both deletional (PAO1 and PAK) and insertional (PA14) mutants in four genes in the P. aeruginosa T3SS, exoS or exoU, exoT, and popB. There were no significant differences in GI colonization among these mutant strains and their WT counterparts, whereas rates of survival following dissemination were significantly decreased in mice infected by the T3SS mutant strains. However, there was a variable, strain-dependent effect on overall survival between parental and T3SS mutants. Thus, increased transcription of genes during in vivo murine GI colonization is not predictive of an essential role for the gene product in either colonization or overall survival following induction of neutropenia

Extracellular DNA Chelates Cations and Induces Antibiotic Resistance in Pseudomonas aeruginosa Biofilms

Biofilms are surface-adhered bacterial communities encased in an extracellular matrix composed of DNA, bacterial polysaccharides and proteins, which are up to 1000-fold more antibiotic resistant than planktonic cultures. To date, extracellular DNA has been shown to function as a structural support to maintain Pseudomonas aeruginosa biofilm architecture. Here we show that DNA is a multifaceted component of P. aeruginosa biofilms. At physiologically relevant concentrations, extracellular DNA has antimicrobial activity, causing cell lysis by chelating cations that stabilize lipopolysaccharide (LPS) and the outer membrane (OM). DNA-mediated killing occurred within minutes, as a result of perturbation of both the outer and inner membrane (IM) and the release of cytoplasmic contents, including genomic DNA. Sub-inhibitory concentrations of DNA created a cation-limited environment that resulted in induction of the PhoPQ- and PmrAB-regulated cationic antimicrobial peptide resistance operon PA3552–PA3559 in P. aeruginosa. Furthermore, DNA-induced expression of this operon resulted in up to 2560-fold increased resistance to cationic antimicrobial peptides and 640-fold increased resistance to aminoglycosides, but had no effect on β-lactam and fluoroquinolone resistance. Thus, the presence of extracellular DNA in the biofilm matrix contributes to cation gradients, genomic DNA release and inducible antibiotic resistance. DNA-rich environments, including biofilms and other infection sites like the CF lung, are likely the in vivo environments where extracellular pathogens such as P. aeruginosa encounter cation limitation

Detection of multiple respiratory pathogens during primary respiratory infection: nasal swab versus nasopharyngeal aspirate using real-time polymerase chain reaction

In this study, we present the multiple detection of respiratory viruses in infants during primary respiratory illness, investigate the sensitivity of nasal swabs and nasopharyngeal aspirates, and assess whether patient characteristics and viral load played a role in the sensitivity. Healthy infants were included at signs of first respiratory tract infection. Paired nasopharyngeal aspirates and nasal swabs were collected. Real-time polymerase chain reaction (PCR) was carried out for 11 respiratory pathogens. Paired nasopharyngeal aspirates and nasal swabs were collected in 98 infants. Rhinovirus (n = 67) and respiratory syncytial virus (n = 39) were the most frequently detected. Co-infection occurred in 48% (n = 45) of the infants. The sensitivity of the nasal swab was lower than the nasopharyngeal aspirate, in particular, for respiratory syncytial virus (51% vs. 100%) and rhinovirus (75% vs. 97%). The sensitivity of the nasal swab was strongly determined by the cycle threshold (CT) value (p < 0.001). The sensitivity of the swab for respiratory syncytial virus, but not rhinovirus, was 100% in children with severe symptoms (score ≥11). It is concluded that, for community-based studies and surveillance purposes, the nasal swab can be used, though the sensitivity is lower than the aspirate, in particular, for the detection of mild cases of respiratory syncytial virus (RSV) infection

Magnesium Limitation Is an Environmental Trigger of the Pseudomonas aeruginosa Biofilm Lifestyle

Biofilm formation is a conserved strategy for long-term bacterial survival in nature and during infections. Biofilms are multicellular aggregates of cells enmeshed in an extracellular matrix. The RetS, GacS and LadS sensors control the switch from a planktonic to a biofilm mode of growth in Pseudomonas aeruginosa. Here we detail our approach to identify environmental triggers of biofilm formation by investigating environmental conditions that repress expression of the biofilm repressor RetS. Mg2+ limitation repressed the expression of retS leading to increased aggregation, exopolysaccharide (EPS) production and biofilm formation. Repression of retS expression under Mg2+ limitation corresponded with induced expression of the GacA-controlled small regulatory RNAs rsmZ and rsmY and the EPS biosynthesis operons pel and psl. We recently demonstrated that extracellular DNA sequesters Mg2+ cations and activates the cation-sensing PhoPQ two-component system, which leads to increased antimicrobial peptide resistance in biofilms. Here we show that exogenous DNA and EDTA, through their ability to chelate Mg2+, promoted biofilm formation. The repression of retS in low Mg2+ was directly controlled by PhoPQ. PhoP also directly controlled expression of rsmZ but not rsmY suggesting that PhoPQ controls the equilibrium of the small regulatory RNAs and thus fine-tunes the expression of genes in the RetS pathway. In summary, Mg2+ limitation is a biologically relevant environmental condition and the first bonafide environmental signal identified that results in transcriptional repression of retS and promotes P. aeruginosa biofilm formation

Gut-central nervous system axis is a target for nutritional therapies

Historically, in the 1950s, the chemist Linus Pauling established a relationship between decreased longevity and obesity. At this time, with the advent of studies involving the mechanisms that modulate appetite control, some researchers observed that the hypothalamus is the "appetite centre" and that peripheral tissues have important roles in the modulation of gut inflammatory processes and levels of hormones that control food intake. Likewise, the advances of physiological and molecular mechanisms for patients with obesity, type 2 diabetes mellitus, inflammatory bowel diseases, bariatric surgery and anorexia-associated diseases has been greatly appreciated by nutritionists. Therefore, this review highlights the relationship between the gut-central nervous system axis and targets for nutritional therapies