965 research outputs found
The termites of the Mayombe Forest Reserve, Congo (Brazzaville): transect sampling reveals an extremely high diversity of ground-nesting soil feeders
No full textEggleton, P., Davies, R. G., Connetable, S., Bignell, D. E., Rouland, C. (2002): The termites of the Mayombe Forest Reserve, Congo (Brazzaville): transect sampling reveals an extremely high diversity of ground-nesting soil feeders. Journal of Natural History 36 (10): 1239-1246, DOI: 10.1080/00222930110048918, URL: http://www.tandfonline.com/doi/abs/10.1080/0022293011004891
Binding and aggulination of Streptococcus pneumoniae by human surfactant protein D (Sp-D) varies between strains but Sp-D fails to enhance killing by neutrophils
No full textRecombinant human surfactant protein D (SP-D) expressed in Escherichia coli, consisting of the head and neck regions of the native molecule, bound to all strains of Streptococcus pneumoniae that were tested, but the extent of binding varied between strains of differing capsular serotypes. The recombinant protein expressed in the yeast Pichia pastoris did not bind. Full-length native SP-D aggregated pneumococci in a calcium-dependent manner that was inhibited by maltose acting as a competitive sugar. The ability of SP-D to modulate the uptake and killing of pneumococci by human neutrophils was also addressed. Neither recombinant truncated SP-D nor native full-length SP-D enhanced the killing of pneumococci by human neutrophils. Aggregation of pneumococci varied not only between strains of the same multilocus sequence type and different serotypes but also between strains of the same serotype. However, use of recombinant strains in which the serotype had been changed showed that the degree of aggregation was influenced by the capsular type. Indeed, a 19F serotype strain which was not aggregated by SP-D did exhibit aggregation when the original isogenic strain was capsule switched to capsular serotype 3. However, although our results show that SP-D is capable of aggregating most pneumococci, no correlation between the degree of aggregation and the capsule or multilocus sequence type of the pneumococcus was clearly apparent. Therefore, although the capsule serotype is not the only determinant of aggregation by SP-D, the data presented here indicate that it does have a role to play
The role of surfactant protein D in the colonisation of the respiratory tract and onset of bacteraemia during pneumococcal pneumonia
No full textWe have shown previously that surfactant protein D (SP-D) binds and agglutinates Streptococcus pneumoniae in vitro. In this study, the role of SP-D in innate immunity against S. pneumoniae was investigated in vivo, by comparing the outcome of intranasal infection in surfactant protein D deficient (SP-D-/-) to wildtype mice (SP-D+/+). Deficiency of SP-D was associated with enhanced colonisation and infection of the upper and lower respiratory tract and earlier onset and longer persistence of bacteraemia. Recruitment of neutrophils to inflammatory sites in the lung was similar in both strains mice in the first 24 hrs post-infection, but different by 48 hrs. T cell influx was greatly enhanced in SP-D-/- mice as compared to SP-D+/+ mice. Our data provides evidence that SP-D has a significant role to play in the clearance of pneumococci during the early stages of infection in both pulmonary sites and blood
Macrofaunal production along the UK continental shelf
No full textEstimates of secondary production (P/B ratio and total production) by macrobenthic communities across the UK continental shelf are presented. Values for individual sampling stations varied from 0.21 to 4.1y-1 for community P/B and 3.1 to 897.2kJm-2y-1 for total production. Such data fills an important gap pertaining to our understanding of the spatial variation in production estimates for this region. Benthic production estimates varied primarily at small (inter-station) scales (24nm), although larger-scale differences were observed. In general, the highest production estimates were exhibited by benthic communities in Cardigan Bay (Irish Sea) and East English Channel, while the lowest estimates were observed for the mid- and northern North Sea areas. The former were typified by shallow, gravelly areas of seabed which exhibit high bed tidal stress and do not thermally stratify during the summer months. On average, annelids contribute an overwhelming majority of the total production with different regions varying in the relative contributions from other phyla such as molluscs, crustaceans and echinoderms.Spatial heterogeneity of sediment granulometric variables occurred primarily between stations while those of other variables (e.g., depth, stratification, and tidal bed stress) were more regional. Although a large proportion of the spatial variation in secondary production estimates was not explained by environmental characteristics, the data indicate that such relationships are scale-dependent. Average bed temperature was a significant factor in creating some of the observed differences at large spatial scales. The possible reasons why a larger proportion of the variation in production estimates was not explained by the present study are presented.</p
Fluid shear contributions to bacteria cell detachment initiated by a monoclonal antibody
No full textReceptor-mediated adhesion of bacteria to biological surfaces is a significant step leading to infection. Due to an increase in bacterial antibiotic resistance, novel methods to block and disrupt these specific interactions have gained considerable interest as possible therapeutic strategies. Recently, several monoclonal antibodies specific for the Staphylococcus aureus collagen receptor demonstrated specialized ability to displace attached cells from collagen in static assays. In this study, we experimentally examine the monoclonal antibody detachment functionality under physiological shear conditions to evaluate the role of this parameter in the detachment process. The detachment of staphylococci from collagen was quantified in real-time using a parallel plate flow chamber, phase contrast video-microscopy and digital image processing. The results demonstrate a unimodal dependence of detachment on fluid wall shear rate. The observed decrease in effective detachment rate with increasing force at the highest shear levels evaluated is counterintuitive and has not been previously demonstrated. Several possible mechanisms of this result are discussed
Tunable acoustic gratings in solid-core photonic bandgap fiber
No full textWe investigate acousto-optic long period grating resonances in a fluid-filled solid-core photonic bandgap fiber (PBGF). The acoustic grating design enables electrically tunable notches in each of the PBGF transmission bands, where both the center frequency and depth of the resonances can be varied. The measured intermodal beat length and resonance bandwidth are in good agreement with numerical simulations based on multipole method. We show that the highly dispersive nature of PBGF modes results in very narrow-band rejection for a given grating pitch. (c) 2007 Optical Society of America.This work was produced with the assistance of the Australian Research Council under the
ARC Centres of Excellence program and supported by the Korea Research Foundation Grant
funded by the Korean Government (MOEHRD, Basic Research Promotion Fund) (KRF-2006-
214-C00029
Applications for fiber Bragg gratings in communications
No full textThe advent of low insertion-loss, high efficiency gratings photoinduced directly in the core of optical fiber leads to a wide range of applications. Optical fiber Bragg grating (OFBG) technology is now "coining of age", with the likely inclusion of fiber gratings in devices to be incorporated in commercial communication systems
Safety and efficacy of hyperbaric oxygen therapy in chronic wound management: current evidence
No full textPublishedReviewCopyright © 2015 Eggleton et al.The breathing of pure oxygen under pressure to treat tissue damage has been employed for almost 45 years and has been investigated through prospective, retrospective and randomized control trials. The physiological effects of oxygen treatment on wound tissue are profound and include the activation of immune cells, changes in cytokine production, and modulation of inflammatory and bactericidal mediators. HBO also influences the biochemistry of whole cells, altering cell proliferation, angiogenesis, clotting and tissue regeneration. The precise effects of HBO on individual cell types and tissues are only beginning to be revealed in both animal and human studies. Many independent studies using HBO adjunctively with standard wound care have observed improved healing, most particularly for diabetic foot ulcers, and can result in a significant reduction in major amputations. Side effects occur infrequently, but myopia, ear barotrauma and rarely oxygen toxicity have been reported. As antibiotics become less available, and clinician time and complex dressings become more expensive, the use of HBO as a means of treating a variety of wound types may become an increasingly appropriate option for treatment.Northcott Devon Medical FoundationDDRC HealthcareUniversity of Exeter Medical Schoo
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