1,657 research outputs found
Epithelial Cell Lysates Induce ExoS Expression and Secretion by Pseudomonas Aeruginosa
The type three secretion system (T3SS) is important for the intracellular survival of Pseudomonas aeruginosa. Known T3SS inducers include low Ca2+, serum or host cell contact. Here, we used corneal epithelial cell lysates to test if host cytosolic factors could also induce the T3SS. Invasive P. aeruginosa strain PAO1 was exposed to cell lysates for 16 h, and expression of T3SS effectors determined by q-PCR and Western immunoblot. Lysate exposure reduced PAO1 growth (∼5-fold) versus trypticase soy broth (TSB), but also resulted in appearance of a protein in culture supernatants, but not bacterial cell pellets, which reacted with antibody raised against ExoS. T3SS-inducing media (TSBi) caused the expression and secretion of ExoS and ExoT. Heat-treated lysates induced the protein; 1:3 diluted lysates did not. The protein that bound anti-ExoS antibody was found in supernatants of lysate-exposed exoT mutants, but not exoS or pscC mutants, suggesting a secreted form of ExoS, albeit slightly larger than that induced by TSBi. Lysate-exposed strain PAK expressed the same protein. Lysates caused PAO1 exoS and exoT gene expression, but only ∼20% and ∼6% of TSBi, respectively. T3SS induction by epithelial cell lysates could help explain T3SS expression by internalized P. aeruginosa
A Comparison of Intermittent and Continuous Exercise Bouts at Different Intensities on Appetite and Postprandial Metabolic Responses in Healthy Men
Exercise intensity affects many potential postprandial responses, but there is limited information on the influence of exercise modality. Therefore, the aim of this study was to investigate if the nature of exercise at two different intensities would affect gastric emptying rate (GER), appetite and metabolic responses following ingestion of a semi-solid meal. Twelve healthy men completed, in a random order, four 60-min cycles at 60% VO2peak (MOD), 40% VO2peak (LOW) and in a continuous (CON) or intermittent (INT) manner. INT consisted of 20 × 1-min exercise bouts with 2-min rest breaks. INT and CON were matched for total work output at each intensity. GER of the post-exercise meal was measured for 2 h using the 13C-breath method. Blood glucose, substrate utilisation and appetite ratings were measured at regular intervals throughout all trials and 24-h energy intake (EI) post-trials was assessed. GER-Delta over Baseline (DOB) was lower (p 0.05). 24-h post-trial EI was similar between LOW-CON vs. LOW-INT (p > 0.05), although MOD-INT vs. MOD-CON 3500 ± 1419 vs. 2556 ± 989 kCal: p < 0.001 was elevated. In summary, MOD-INT exercise delays GER without stimulating perceived appetite in the 2 h period after meal ingestion, although EI was greater in the 24-h post-trial
Singing teaching as a therapy for chronic respiratory disease - a randomised controlled trial and qualitative evaluation
<p>Abstract</p> <p>Background</p> <p>Despite optimal pharmacological therapy and pulmonary rehabilitation, patients with COPD continue to be breathless. There is a need to develop additional strategies to alleviate symptoms. Learning to sing requires control of breathing and posture and might have benefits that translate into daily life.</p> <p>Methods</p> <p>To test this hypothesis we performed a randomised controlled trial, comparing a six week course of twice weekly singing classes to usual care, in 28 COPD patients. The experience of singing was assessed in a qualitative fashion, through interviews with a psychologist. In addition, we surveyed patients with chronic respiratory conditions who participated in a series of open singing workshops.</p> <p>Results</p> <p>In the RCT, the physical component score of the SF36 improved in the singers (n = 15) compared to the controls (n = 13); +7.5(14.6) vs. -3.8(8.4) p = 0.02. Singers also had a significant fall in HAD anxiety score; -1.1(2.7) vs. +0.8(1.7) p = 0.03. Singing did not improve single breath counting, breath hold time or shuttle walk distance. In the qualitative element, 8 patients from the singing group were interviewed. Positive effects on physical sensation, general well-being, community/social support and achievement/efficacy emerged as common themes. 150 participants in open workshops completed a questionnaire. 96% rated the workshops as "very enjoyable" and 98% thought the workshop had taught them something about breathing in a different way. 81% of attendees felt a "marked physical difference" after the workshop.</p> <p>Conclusion</p> <p>Singing classes can improve quality of life measures and anxiety and are viewed as a very positive experience by patients with respiratory disease; no adverse consequences of participation were observed.</p> <p>Trial Registration</p> <p>Current Controlled Trials - ISRCTN17544114.</p
Holography, Pade Approximants and Deconstruction
We investigate the relation between holographic calculations in 5D and the
Migdal approach to correlation functions in large N theories. The latter
employs Pade approximation to extrapolate short distance correlation functions
to large distances. We make the Migdal/5D relation more precise by quantifying
the correspondence between Pade approximation and the background and boundary
conditions in 5D. We also establish a connection between the Migdal approach
and the models of deconstructed dimensions.Comment: 28 page
Methane metabolism in the archaeal phylum Bathyarchaeota revealed by genome-centric metagenomics
Methanogenic and methanotrophic archaea play important roles in the global flux of methane. Culture-independent approaches are providing deeper insight into the diversity and evolution of methane-metabolizing microorganisms, but, until now, no compelling evidence has existed for methane metabolism in archaea outside the phylum Euryarchaeota. We performed metagenomic sequencing of a deep aquifer, recovering two near-complete genomes belonging to the archaeal phylum Bathyarchaeota (formerly known as the Miscellaneous Crenarchaeotal Group). These genomes contain divergent homologs of the genes necessary for methane metabolism, including those that encode the methyl–coenzyme M reductase (MCR) complex. Additional non-euryarchaeotal MCR-encoding genes identified in a range of environments suggest that unrecognized archaeal lineages may also contribute to global methane cycling. These findings indicate that methane metabolism arose before the last common ancestor of the Euryarchaeota and Bathyarchaeota
Higgs Phenomenon for 4-D Gravity in Anti de Sitter Space
We show that standard Einstein gravity coupled to a free conformal field
theory (CFT) in Anti de Sitter space can undergo a Higgs phenomenon whereby the
graviton acquires a nonzero mass (and three extra polarizations). We show that
the essential ingredients of this mechanism are the discreteness of the energy
spectrum in AdS space, and unusual boundary conditions on the elementary fields
of the CFT. These boundary conditions can be interpreted as implying the
existence of a 3-d defect CFT living at the boundary of the AdS space. Our
free-field computation sheds light on the essential, model-independent features
of AdS that give rise to massive gravity.Comment: 17 page
A dynamic framework for assessing and managing risks to ecosystems from fisheries: demonstration for conserving the krill-based food web in Antarctica
The ecosystem approach to fisheries has been discussed since the 1980s. It aims to reduce risks from fisheries to whole, or components of, ecosystems, not just to target species. Precautionary approaches further aim to keep the risk of damage to a low level. Here, we provide a dynamic framework for spreading the ecosystems risk of fisheries in space and time, a method that can be used from the outset of developing fisheries and continually updated as new knowledge becomes available. Importantly, this method integrates qualitative and quantitative approaches to assess risk and provides mechanisms to both spread the risk, including enabling closed areas to help offset risk, and adjust catch limits to keep regional risk to a baseline level. Also, the framework does not require uniform data standards across a region but can incorporate spatially and temporally heterogeneous data and knowledge. The approach can be coupled with the conservation of biodiversity in marine protected areas, addressing potential overlap of fisheries with areas of high conservation value. It accounts for spatial and temporal heterogeneity in ecosystems, including the different spatial and temporal scales at which organisms function. We develop the framework in the first section of the paper, including a simple illustration of its application. In the framework we include methods for using closed areas to offset risk or for conserving biodiversity of high conservation value. We also present methods that could be used to account for uncertainties in input data and knowledge. In the second section, we present a real-world illustration of the application of the framework to managing risks of food web effects of fishing for Antarctic krill in the Southern Ocean. Last, we comment on the wider application and development of the framework as information improves
Diurnal influences of fasted and non-fasted brisk walking on gastric emptying rate, metabolic responses, and appetite in healthy males
Growing evidence suggests circadian rhythms, nutrition and metabolism are intimately linked. Intermittentfasting (IMF) has become an increasingly popular intervention for metabolic health and combining IMF withexercise may lead to benefits for weight management. However, little is known about the diurnal variation offasted exercise. This study aimed to investigate the diurnal influences on gastric emptying rate (GER), metabolicresponses, and appetite to fasted and non-fasted exercise. Twelve healthy males completed four 45 min walks ina randomised order. Walks were completed in the morning (AM) and evening (PM) and either fasted (FASTED)or after consumption of a standardised meal (FED). GER of a semi-solid lunch was subsequently measured for 2 husing the13C breath test. Blood glucose concentration, substrate utilisation, and ratings of appetite were mea-sured throughout. Energy intake was also assessed for the following 24 h. GER Tlagwas slower in PM-FASTEDcompared to AM-FASTED, AM-FED, and PM-FED (75 ± 18 min vs. 63 ± 14 min,P= 0.001, vs. 65 ± 10 min,P= 0.028 and vs. 67 ± 16 min,P= 0.007). Blood glucose concentration was greater in the FED trials incomparison to the FASTED trials pre-lunch (P 0.05) or 24 h post-energy intake (P= 0.476). Thesefindings suggest that evening fasted exercise results in delayed GER, withoutchanges in appetite. No compensatory effects were observed for appetite, and 24 h post-energy intake for bothfasted exercise trials, therefore, increased fat oxidation holds positive implications for weight management
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Evaluating the taxa that provide shared pollination services across multiple crops and regions
Many pollinator species visit multiple crops in multiple regions, yet we know little about their pollination service provisioning at local and regional scales. We investigated the floral visitors (n = 13,200), their effectiveness (n = 1718 single visits) and response to landscape composition across three crops avocado, mango and macadamia within a single growing region (1 year), a single crop (3 years) and across different growing regions in multiple years. In total, eight wild visitor groups were shared across all three crops. The network was dominated by three pollinators, two bees (Apis mellifera and Tetragonula spp.) and a fly, Stomorhina discolor. The visitation network for the three crops was relatively generalised but with the addition of pollen deposition data, specialisation increased. Sixteen managed and wild taxa were consistently present across three years in avocado, yet their contribution to annual network structure varied. Node specialisation (d’) analyses indicated many individual orchard sites across each of the networks were significantly more specialised compared to that predicted by null models, suggesting the presence of site-specific factors driving these patterns. Identifying the taxa shared across multiple crops, regions and years will facilitate the development of specific pollinator management strategies to optimize crop pollination services in horticultural systems
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