Biofilm form and function: carbon availability affects biofilm architecture, metabolic activity and planktonic cell yield.

AIMS: To investigate carbon transformation by biofilms and changes in biofilm architecture, metabolic activity and planktonic cell yield in response to fluctuating carbon availability. METHODS AND RESULTS: Pseudomonas sp. biofilms were cultured under alternating carbon-replete and carbon-limited conditions. A shift to medium without added carbon led to a 90% decrease in biofilm respiration rate and a 40% reduction in planktonic cell yield within 1 h. Attached cell division and progeny release were shown to contribute to planktonic cell numbers during carbon limitation. Development of a significantly enlarged biofilm surface area during carbon limitation facilitated a rapid increase in whole-biofilm metabolic activity, cell yield and biomass upon the re-introduction of carbon after 8 days of limitation. The cumulative number of planktonic cells (>10(10) CFU) released from the biofilm during the cultivation period contained only 1·0% of the total carbon available to the biofilm, with 6·5% of the carbon retained in the biofilm and 54% mineralized to CO(2) . CONCLUSIONS: Biofilm-derived planktonic cell yield is a proliferation mechanism. The rapid response of biofilms to environmental perturbations facilitates the optimal utilization of resources to promote both proliferation and survival. Biofilms function as efficient catalysts for environmental carbon transformation and mineralization. SIGNIFICANCE AND IMPACT OF THE STUDY: A greater understanding of the relationship between biofilm form and function can inform strategies intended to control and/or promote biofilm formation.

Anaerobic treatability and biogas production potential of selected in-mill streams.

Biochemical methane potential assays (BMP assays) were performed to study the potential of anaerobic treatment of in-mill wastewaters. The assay results indicated that condensate and the BCTMP effluent, which are currently treated with the anaerobic internal circulation reactors, were the best streams for anaerobic treatment because of their relatively high degradability (>80%) and initial rates of biogas production. The softwood dewatering process stream was the worst with the lowest degradability (~30%). The hardwood stream was more degradable than the softwood stream from the same process. Biogas production was found to be additive and predictable in blended samples. In addition, degradability was found to be negatively correlated to the concentration of dehydroabietic acid and tannin-lignin compounds. The anaerobic treatment of the suitable streams has great potential value with significantly reduced sludge production and energy savings.

In vitro activity of fusidic acid and mupirocin against coagulase-positive staphylococci from pets.

OBJECTIVES: Methicillin-resistant Staphylococcus aureus (MRSA) and multiresistant Staphylococcus pseudintermedius (MRSP) have emerged as important pathogens in animal infections. Associated therapeutic problems and the zoonotic potential of staphylococci have renewed interest in topical antibiotics for treatment and carrier decolonization. Fusidic acid and mupirocin are used topically in humans and animals but resistant strains isolated from people are increasing. This study investigates the in vitro activity of fusidic acid and mupirocin against coagulase-positive staphylococci from pets. METHODS: A collection of 287 staphylococci was examined, comprising 102 MRSA, 102 methicillin-susceptible S. aureus, 71 S. pseudintermedius and 12 MRSP from canine and feline infections and carrier sites isolated in the UK and Germany. MICs were determined by the agar dilution method according to CLSI (formerly NCCLS) standards. RESULTS: The majority (89.7%) of all MICs were

Engineered heparins: novel beta-secretase inhibitors as potential Alzheimer's disease therapeutics.

BACKGROUND: Cleavage of beta-amyloid precursor protein (APP) by the protease beta-secretase (BACE1) is a key step in beta-amyloid peptide processing. We have described a novel role for heparan sulphate polysaccharides in Alzheimer's disease pathology as naturally occurring inhibitors of beta-secretase, suggesting new avenues for discovery of novel drugs for Alzheimer's disease based on heparins. OBJECTIVE: To evaluate engineered heparin analogues as novel beta-secretase inhibitors in vitro, including modifications to increase bioavailability. METHODS: We tested a number of selectively desulphated and chemically modified heparins for their ability to inhibit BACE1 and other proteases in vitro using APP fluorescent resonance energy transfer peptide substrates RESULTS: Several lead compounds have been identified that are effective beta-secretase inhibitors, but have negligible activity as anticoagulants or as inhibitors of other aspartyl proteases structurally related to beta-secretase. In addition, the compounds studied also give some insight into the structural interaction between beta-secretase and heparin, indicating that the structure of the polysaccharide is much more important than charge. CONCLUSION: We have demonstrated that modifications to increase bioavailability of chemically modified heparins have little effect on their efficacy as beta-secretase inhibitors. Therefore, these heparins show promise for development as a novel class of pharmaceuticals that target the underlying pathology of Alzheimer's disease. We have also found further evidence that it is the structure of the polysaccharide that is important for the interaction with beta-secretase, not simply the level of sulphation or charge.

Dechlorination after thermal treatment of a TCE-contaminated aquifer: laboratory experiments.

A microcosm study was conducted to evaluate dechlorination of trichloroethene (TCE) to ethene and survival of dechlorinating bacteria after a thermal treatment in order to explore the potential for post-thermal bioremediation. Unamended microcosms containing groundwater and aquifer material from a contaminated site dechlorinated TCE to cis-1,2-dichloroethene (cDCE), while lactate-amended microcosms dechlorinated TCE to cDCE or ethene. A thermal treatment was simulated by heating a sub-set of microcosms to 100 degrees C for 10d followed by cooling to 10 degrees C over 150 d. The heated microcosms demonstrated no dechlorination when unamended. However, when amended with lactate, cDCE was produced in 2 out of 6 microcosms within 300 d after heating. Dechlorination of TCE to cDCE thus occurred in fewer heated (2 out of 12) than unheated (10 out of 12) microcosms. In unheated microcosms, the presence of dechlorinating microorganisms, including Dehalococcoides, was confirmed using nested PCR of 16S rRNA genes. Dechlorinating microorganisms were detected in fewer microcosms after heating, and Dehalococcoides were not detected in any microcosms after heating. Dechlorination may therefore be limited after a thermal treatment in areas that have been heated to 100 degrees C. Thus, inflow of groundwater containing dechlorinating microorganisms and/or bioaugmention may be needed for anaerobic dechlorination to occur after a thermal treatment.

Effect of phosphorus limitation on microbial floc structure and gene expression in activated sludge.

The effect of limiting phosphorus (P) in activated sludge was investigated in laboratory-scale sequencing batch reactors (SBRs). Correlative microscopy revealed that P-limitation (COD:N:P = 100:5:0.05) leads to morphological changes in floc structure and the composition of extracellular polymeric substances (EPS). This was found to be accompanied by expression of quorum-sensing in an acyl homoserine lactone bioassay. Differential gene expression in relation to P-limitation was examined in a global profile using the Affymetrix Escherichia coli antisense genomic microarray. Three separate experiments were conducted where the impact of P-limitation was examined under batch conditions and in SBRs at stable operating conditions and within 3-7 days following a down-shift in P. Significant changes in open reading frames (ORF) and intergenic regions based on the E. coli microarray were observed. Several genes associated with cell structure, including slt, wbbH, fimH, amB, rfaJ and slp were found to be expressed. Quorum regulated genes were also found to be expressed including psiF which is known to be induced by P-starvation (92% confidence level; 1.45 log ratio).

Gamification for health promotion: systematic review of behaviour change techniques in smartphone apps.

OBJECTIVE: Smartphone games that aim to alter health behaviours are common, but there is uncertainty about how to achieve this. We systematically reviewed health apps containing gaming elements analysing their embedded behaviour change techniques. METHODS: Two trained researchers independently coded apps for behaviour change techniques using a standard taxonomy. We explored associations with user ratings and price. DATA SOURCES: We screened the National Health Service (NHS) Health Apps Library and all top-rated medical, health and wellness and health and fitness apps (defined by Apple and Google Play stores based on revenue and downloads). We included free and paid English language apps using 'gamification' (rewards, prizes, avatars, badges, leaderboards, competitions, levelling-up or health-related challenges). We excluded apps targeting health professionals. RESULTS: 64 of 1680 (4%) health apps included gamification and met inclusion criteria; only 3 of these were in the NHS Library. Behaviour change categories used were: feedback and monitoring (n=60, 94% of apps), reward and threat (n=52, 81%), and goals and planning (n=52, 81%). Individual techniques were: self-monitoring of behaviour (n=55, 86%), non-specific reward (n=49, 82%), social support unspecified (n=48, 75%), non-specific incentive (n=49, 82%) and focus on past success (n=47, 73%). Median number of techniques per app was 14 (range: 5-22). Common combinations were: goal setting, self-monitoring, non-specific reward and non-specific incentive (n=35, 55%); goal setting, self-monitoring and focus on past success (n=33, 52%). There was no correlation between number of techniques and user ratings (p=0.07; rs=0.23) or price (p=0.45; rs=0.10). CONCLUSIONS: Few health apps currently employ gamification and there is a wide variation in the use of behaviour change techniques, which may limit potential to improve health outcomes. We found no correlation between user rating (a possible proxy for health benefits) and game content or price. Further research is required to evaluate effective behaviour change techniques and to assess clinical outcomes. TRIAL REGISTRATION NUMBER: CRD42015029841.

Nitric oxide levels and ciliary beat frequency in indigenous New Zealand children.

New Zealand children's morbidity from respiratory disease is high. This study examines whether subclinical ciliary abnormalities underlie the increased prevalence of respiratory disease in indigenous New Zealand children. A prospective study enrolled a group of healthy children who were screened for respiratory disease by questionnaire and lung function. Skin-prick tests were performed to control for atopy. Exhaled and nasal NO was measured online by a single-breath technique using chemiluminescence. Ciliary specimens were obtained by nasal brushings for assessment of structure and function. The ciliary beat frequency (CBF) (median CBF, 12.5 Hz; range, 10.4-16.8 Hz) and NO values (median exhaled NO, 5.6 ppb; range, 2.3-87.7 ppb; median nasal NO, 403 ppb; range, 34-1,120 ppb) for healthy New Zealand European (n=58), Pacific Island (n=61), and Maori (n=16) children were comparable with levels reported internationally. No ethnic differences in NO, atopy, or CBF were demonstrated. Despite an apparently normal ciliary beat, the percentage of ciliary structural defects was 3 times higher than reported controls (9%; range, 3.6-31.3%), with no difference across ethnic groups. In conclusion, it is unlikely that subclinical ciliary abnormalities underlie the increased prevalence of respiratory disease in indigenous New Zealand children. The high percentage of secondary ciliary defects suggests ongoing environmental or infective damage.

Plasma cholesterol esterification and transfer, the menopause, and hormone replacement therapy in women.

With the onset of the menopause, plasma lipids and lipoprotein metabolism changes toward a more atherogenic profile that is improved by HRT. To determine whether cholesterol esterification rate (CER) and transfer of cholesteryl esters from high density lipoproteins to apolipoprotein B-containing lipoproteins are affected by menopause and HRT, plasma newly synthesized cholesteryl ester transfer (NCET) activity, CER and plasma lipids, lipoproteins, and apolipoprotein concentrations were measured in perimenopausal women (age range: 40-55 yr), including 49 premenopausal women and 32 postmenopausal women who were subsequently randomized to receive either placebo or 17-beta estradiol/norethisterone for 6 months. Plasma NCET (P = 0.03) and CER (P = 0.008) were significantly higher in postmenopausal women. Plasma low density lipoprotein cholesterol concentration, high density lipoprotein concentration, and body mass index were independent predictors of plasma NCET in premenopausal women, and plasma triglyceride and apolipoprotein B concentrations were corresponding predictors in postmenopausal women. When data were adjusted for plasma triglyceride, plasma NCET activity was no longer significantly different (P = 0.81) between premenopausal and postmenopausal women. Plasma NCET and CER did not change significantly in postmenopausal women during HRT. These data suggest that the determinants of plasma NCET activity after menopause and increased levels of triglyceride-rich lipoprotein acceptors of cholesteryl esters may lead to increased plasma NCET that is not reduced by HRT in postmenopausal women.

Visualization by immune electron microscopy of viruses associated with acute respiratory disease.

A sensitive and rapid method for detecting adenovirus and influenza viruses has been demonstrated by using both the direct and indirect immune electron microscopy technique. The indirect method was from 4 to over 32 times more sensitive than the direct method. The technique appears to have the sensitivity approaching tissue culture methods, but is much more rapid, requires less laboratory support personnel and space, and should lend itself to detection of noncytologic agents. These data suggest a new role for the electron microscope in diagnostic virology.

Plasma cholesteryl ester fatty acid composition, insulin sensitivity, the menopause and hormone replacement therapy.

This study was designed to determine the effect of menopause and hormone replacement therapy (HRT) on plasma cholesteryl ester fatty acid (CEFA) composition and insulin sensitivity and the relationships between these variables in perimenopausal women (aged 40-55 years) including 49 who were premenopausal and 32 who were postmenopausal. Plasma cholesteryl ester proportions of dihomo-gamma-linolenic acid (20:3 n-6) were correlated significantly with insulin sensitivity index (r=-0.319, P=0.005), fasting serum insulin levels (r=0.230, P=0.038), body mass index (r=0.242, P=0.03) and per cent body fat (r=0.329, P=0.003) in perimenopausal women (n=81). Similar associations were observed in premenopausal women. Regression analysis suggested the relationships between 20:3 n-6 proportions and indices of insulin action may be partly mediated by levels of adiposity. In postmenopausal women, 6 months of HRT significantly (P=0.008) increased the ratio of arachidonic acid (20:4 n-6) to linoleic acid (18:2 n-6), which is an indicator of activity in the pathway of 20:4 n-6 synthesis, compared with placebo. These findings suggest that the type of fat in the diet indicated by plasma CEFA composition is linked to adiposity and insulin action. They also suggest that in postmenopausal women, HRT may increase the synthesis of 20:4 n-6, which is the precursor for eicosanoids with important cardiovascular functions.

The effects of sequential combined oral 17beta-estradiol norethisterone acetate on insulin sensitivity and body composition in healthy postmenopausal women: a randomized single blind placebo-controlled study.

OBJECTIVE: The androgenic effect of progestogen, necessary in early postmenopausal hormone replacement therapy (HRT), may adversely affect insulin sensitivity as well as body fat distribution and thereby increase the cardiovascular risk profile. The impact of HRT with sequential combined oral 17beta-estradiol and norethisterone acetate on insulin sensitivity and body composition in early menopause has not been studied. DESIGN: A randomized single blind placebo-controlled 6-month study of sequential combined 17beta-estradiol norethisterone acetate on insulin sensitivity and body composition was carried out. Thirty fit healthy postmenopausal women were enrolled and completed this 6-month study. Body composition was measured by dual-energy x-ray absorptiometry scanning, and insulin sensitivity was measured using the euglycemic hyperinsulinemic clamp. Studies were undertaken at baseline and after 6 months of therapy. The studies were performed during the estrogen-only phase of therapy. RESULTS: All women demonstrated a degree of decreased insulin sensitivity that was not modified by 6 months of hormone replacement therapy. Body composition remained unchanged over 6 months. There was no alteration in total body fat or the distribution of body fat. The percentage of central abdominal fat (android) was not altered. CONCLUSION: Six months of HRT with sequential combined oral 17beta-estradiol norethisterone acetate does not have an adverse effect on insulin sensitivity and does not promote an increase in weight or the more android distribution of body fat, which could contribute to the increased cardiovascular risk profile that is evident in postmenopausal women.

Scope and limitations of collateral circulation. Presidential address.

The human body, possessing no true end arteries, is capable of furnishing some collateral vessels for any arterial, venous, or lymphatic obstruction. In places, only capillary anastomoses are immediately available and ischemia may be profound. We have learned to support organs like the heart, brain, or liver while small communications enlarge to increase the flow of blood or lymph. Even in the retina, some success has been obtained by retrograde perfusion through the supra-orbital artery. Supplemental flow, ie, blood varying in content or pressure--such as bronchial blood substituting for pulmonary blood--carries some detriment in the form of diminished function or the rupture of thin-walled vessels.

Retrospective review of children presenting with non cystic fibrosis bronchiectasis: HRCT features and clinical relationships.

Non cystic fibrosis (CF) bronchiectasis in children presents with a spectrum of disease severity. Our aims were to document the extent and severity of disease in children with non-CF bronchiectasis, to review the inter- and intraobserver agreement for the high-resolution computed tomography (HRCT) features examined, and to assess correlations between HRCT features and clinical measures of severity. We performed a retrospective review of 56 children from the Starship Children's Hospital. HRCT scans were scored by a modified Bhalla system, and the chest X-rays using the Brasfield score. Scores were correlated with demographics, number of hospitalizations, disease duration, pulmonary function, clinical examination, and chronic sputum infection. The bronchiectasis seen was widespread and severe, particularly in Maori and Pacific Island children. The kappa coefficient for intraobserver agreement was better than that for interobserver agreement. Comparisons between HRCT scan and lung function parameters showed that the strongest relationships were between forced expiratory volume in 1 sec (FEV(1)) and forced expiratory flow between 25-75% of forced vital capacity (FEF(25-75)) with the extent of bronchiectasis, bronchial wall thickening, and air trapping. Children with digital clubbing and chest deformity showed significantly higher scores for extent of bronchiectasis, bronchial wall dilatation and thickness, and overall computed tomography (CT) score. No relationship was demonstrated between chronic sputum infection and CT score. The HRCT score demonstrated a stronger correlation between the extent and severity of bronchiectasis, and spirometry values, than the chest X-ray score. In conclusion, pediatric non-CF bronchiectasis in Auckland is extensive and severe. The good intraobserver ratings mean that consistency of scoring is possible on repeated scans. This study cannot comment on the relationships of CT and less severe disease.

Aberrant response to commensal Bacteroides thetaiotaomicron in Crohn's disease: an ex vivo human organ culture study.

BACKGROUND: Human ex vivo evidence indicating that an inappropriate immune response(s) to nonpathogenic bacteria contributes to disease pathogenesis in pediatric Crohn's disease (CD) is limited. The aim of the present study was to compare and contrast the early innate immune response of pediatric "healthy" versus CD mucosa to pathogenic, probiotic, and commensal bacteria. METHODS: "Healthy control" and CD pediatric mucosal biopsies (terminal ileum and transverse colon) were cocultured for 8 hours with E. coli O42, Lactobacillus GG (LGG), Bacteroidesthetaiotaomicron (B. theta), or stimulated with interleukin (IL)-1ß (positive control). Matched nonstimulated biopsies served as experimental controls. IL-8 was the immune marker of choice. IL-8 mRNA and protein levels were quantified by quantitative polymerase chain reaction and sandwich enzyme-linked immunosorbent assay, respectively. RESULTS: IL-8 secretion was observed when control, ileal biopsies were exposed to pathogenic O42 and probiotic LGG, with no response noted to commensal B. theta. In comparison, Crohn's ileal biopsies showed impaired ability to induce IL-8 in response to O42 and LGG. Control colonic tissue showed a limited response to O42 or B. theta and LGG significantly reduced IL-8 secretion. Unlike control tissue, however, Crohn's ileal and colonic tissue did respond to B. theta, with more enhanced expression in the colon. CONCLUSIONS: We provide the first ex vivo data to support the notion that aberrant mucosal recognition of commensal bacteria may contribute to pediatric CD. While IL-8 responses to O42 and LGG varied with disease status and anatomical location, B. theta consistently induced significant IL-8 both in ileal and colonic CD tissue, which was not seen in control, healthy tissue.