Multimode fibre:Light-sheet microscopy at the tip of a needle

We also thank the UK Engineering and Physics Sciences Research Council for funding under grant EP/J01771X/1. Finally, we would like to thank EXCELLENT TEAMS (CZ.1.07/2.3.00/30.0005) from European Social Fund and CEITEC - Central European Institute of Technology (CZ.1.05/1.1.00/02.0068) from European Regional Development Fund for support.Light-sheet fluorescence microscopy has emerged as a powerful platform for 3-D volumetric imaging in the life sciences. Here, we introduce an important step towards its use deep inside biological tissue. Our new technique, based on digital holography, enables delivery of the light-sheet through a multimode optical fibre - an optical element with extremely small footprint, yet permitting complex control of light transport processes within. We show that this approach supports some of the most advanced methods in light-sheet microscopy: by taking advantage of the cylindrical symmetry of the fibre, we facilitate the wavefront engineering methods for generation of both Bessel and structured Bessel beam plane illumination. Finally, we assess the quality of imaging on a sample of fluorescent beads fixed in agarose gel and we conclude with a proof-of-principle imaging of a biological sample, namely the regenerating operculum prongs of Spirobranchus lamarcki.Publisher PDFPeer reviewe

Eco-epidemiological analysis of rickettsial seropositivity in rural areas of Colombia: A multilevel approach

ABSTARCT: Rickettsiosis is a re-emergent infectious disease without epidemiological surveillance in Colombia. This disease is generally undiagnosed and several deadly outbreaks have been reported in the country in the last decade. The aim of this study is to analyze the eco-epidemiological aspects of rickettsial seropositivity in rural areas of Colombia where outbreaks of the disease were previously reported. A cross-sectional study, which included 597 people living in 246 households from nine hamlets in two municipalities of Colombia, was conducted from November 2015 to January 2016. The survey was conducted to collect sociodemographic and household characteristics (exposure) data. Blood samples were collected to determine the rickettsial seropositivity in humans, horses and dogs (IFA, cut-off = 1/128). In addition, infections by rickettsiae were detected in ticks from humans and animals by real-time PCR targeting gltA and ompA genes. Data was analyzed by weighted multilevel clog-log regression model using three levels (person, household and hamlets) and rickettsial seropositivity in humans was the main outcome. Overall prevalence of rickettsial seropositivity in humans was 25.62% (95%CI 22.11-29.12). Age in years (PR = 1.01 95%CI 1.01-1.02) and male sex (PR = 1.65 95%CI 1.43-1.90) were risk markers for rickettsial seropositivity. Working outdoors (PR = 1.20 95%CI 1.02-1.41), deforestation and forest fragmentation for agriculture use (PR = 1.75 95%CI 1.51-2.02), opossum in peridomiciliary area (PR = 1.56 95%CI 1.37-1.79) and a high proportion of seropositive domestic animals in the home (PR20-40% vs 40% vs <20% = 3.14 95%CI 2.43-4.04) were associated with rickettsial seropositivity in humans. This study showed the presence of Rickettsia antibodies in human populations and domestic animals. In addition, different species of rickettsiae were detected in ticks collected from humans and animals. Our results highlighted the role of domestic animals as sentinels of rickettsial infection to identify areas at risk of transmission, and the importance of preventive measures aimed at curtailing deforestation and the fragmentation of forests as a way of reducing the risk of transmission of emergent and re-emergent pathogens

Local regulation of [(3)H]-noradrenaline release from the isolated guinea-pig right atrium by P(2X)-receptors located on axon terminals

1. In this study the regulation of cardiac sympathetic outflow by presynaptic P(2X) receptor-gated ion channels was examined. 2. ATP (30 μM–1 mM) and other P2-receptor agonists elicited [(3)H]-noradrenaline ([(3)H]-NA) outflow from the isolated guinea-pig right atrium with the potency order of ATP>2-methyl-thioATP>α,β-methylene-ATP=ADP, whereas β,γ-methylene-L-ATP was inactive. 3. Ca(2+)-free conditions abolished both electrical field stimulation (EFS)- and ATP-evoked release of tritium. Unlike from EFS-induced outflow, ATP-induced [(3)H]-NA outflow was not reduced by ω-Conotoxin-GVIA (100 nM), Cd(2+) (100 μM) and tetrodotoxin (1 μM). 4. The rapid extracellular decomposition of ATP was revealed by HPLC analysis. However, the effect of ATP to promote [(3)H]-NA release was not prevented by 8-cyclopentyl-1,3-dipropylxanthine (DPCPX, 250 nM), 3,7-dimethyl-1-propargylxanthine (DMPX, 250 nM), or by reactive blue 2 (RB2, 10 μM), antagonists of A(1)-, A(2)- and inhibitory P(2) receptors. 5. Zn(2+) (50 μM), the P(2X)-receptor modulator potentiated, and P(2X) receptor antagonists, i.e. suramin (300 μM), pyridoxal-phosphate-6-azophenyl-2′,4′-disulphonic acid (PPADS, 30 μM) and 2′-o-(trinitrophenyl)-adenosine 5′-triphosphate (TNP-ATP, 30 μM) antagonized the ATP (1 mM)-evoked response. 6. RT–PCR study revealed the expression of P(2X2) and P(2X3) receptor mRNAs in guinea-pig superior cervical ganglion. 7. PPADS (30 μM) significantly reduced the EFS-induced [(3)H]-NA outflow in the presence DPCPX (250 nM) and RB2 (10 μM). 8. In summary a P(2X)-type purinoceptor regulates noradrenaline release from the isolated right atrium of the guinea-pig. The pharmacological profile of the receptor resemble to homo-oligomeric P(2X3) or hetero-oligomeric P(2X2)/P(2X3) complexes, and provide a new target to intervene on sympathetic neuroeffector transmission at the presynaptic site