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31.
Cronin M Akin AR Collins SA Meganck J Kim JB Baban CK Joyce SA van Dam GM Zhang N van Sinderen D O'Sullivan GC Kasahara N Gahan CG Francis KP Tangney M 《PloS one》2012,7(1):e30940
The ability to track microbes in real time in vivo is of enormous value for preclinical investigations in infectious disease or gene therapy research. Bacteria present an attractive class of vector for cancer therapy, possessing a natural ability to grow preferentially within tumours following systemic administration. Bioluminescent Imaging (BLI) represents a powerful tool for use with bacteria engineered to express reporter genes such as lux. BLI is traditionally used as a 2D modality resulting in images that are limited in their ability to anatomically locate cell populations. Use of 3D diffuse optical tomography can localize the signals but still need to be combined with an anatomical imaging modality like micro-Computed Tomography (μCT) for interpretation.In this study, the non-pathogenic commensal bacteria E. coli K-12 MG1655 and Bifidobacterium breve UCC2003, or Salmonella Typhimurium SL7207 each expressing the luxABCDE operon were intravenously (i.v.) administered to mice bearing subcutaneous (s.c) FLuc-expressing xenograft tumours. Bacterial lux signal was detected specifically in tumours of mice post i.v.-administration and bioluminescence correlated with the numbers of bacteria recovered from tissue. Through whole body imaging for both lux and FLuc, bacteria and tumour cells were co-localised. 3D BLI and μCT image analysis revealed a pattern of multiple clusters of bacteria within tumours. Investigation of spatial resolution of 3D optical imaging was supported by ex vivo histological analyses. In vivo imaging of orally-administered commensal bacteria in the gastrointestinal tract (GIT) was also achieved using 3D BLI. This study demonstrates for the first time the potential to simultaneously image multiple BLI reporter genes three dimensionally in vivo using approaches that provide unique information on spatial locations. 相似文献
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Synopsis A cytochemical study has been made of acid -glycerophosphatase, acid naphthol-AS-BI-phosphatase and naphthol esterase activities during the induction of crown gall inLycopersicon esculentum byAgrobacterium tumefaciens. There was an increased activity of these enzymes with time after infection, being more marked for the phosphatases than the esterases. It is suggested that the esterase activities may play a part in cell wall development of the maturing gall. 相似文献
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Improved Luciferase Tagging System for Listeria monocytogenes Allows Real-Time Monitoring In Vivo and In Vitro 下载免费PDF全文
Christian U. Riedel Ian R. Monk Pat G. Casey David Morrissey Gerald C. O'Sullivan Mark Tangney Colin Hill Cormac G. M. Gahan 《Applied microbiology》2007,73(9):3091-3094
An improved system for luciferase tagging Listeria monocytogenes was developed by constructing a highly active, constitutive promoter. This construct gave 100-fold-higher activity in broth than any native promoter tested and allowed for imaging of lux-tagged L. monocytogenes in food products, during murine infections, and in tumor targeting studies. 相似文献
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Sarah J. Smith Christopher J. Noble Randahl C. Palmer Graeme R. Hanson Gerhard Schenk Lawrence R. Gahan Mark J. Riley 《Journal of biological inorganic chemistry》2008,13(4):499-510
A binuclear copper complex, [Cu2(BPMP)(OAc)2][ClO4]·H2O, has been prepared using the binucleating ligand 2,6-bis[bis(pyridin-2-ylmethylamino)methyl]-4-methylphenol (H-BPMP). The
X-ray crystal structure reveals the copper centers to have a five-coordinate square pyramidal geometry, with the acetate ligands
bound terminally. The bridging phenolate occupies the apical position of the square-based pyramids and magnetic susceptibility,
electron paramagnetic resonance (EPR) and variable-temperature variable-field magnetic circular dichroism (MCD) measurements
indicate that the two centers are very weakly antiferromagnetically coupled (J = −0.6 cm−1). Simulation of the dipole–dipole-coupled EPR spectrum showed that in solution the Cu–O–Cu angle was increased from 126°
to 160° and that the internuclear distance was larger than that observed crystallographically. The high-resolution spectroscopic
information obtained has been correlated with a detailed ligand-field analysis to gain insight into the electronic structure
of the complex. Symmetry arguments have been used to demonstrate that the sign of the MCD is characteristic of the tetragonally
elongated environment. The complex also displays catecholase activity (k
cat = 15 ± 1.5 min−1, K
M = 6.4 ± 1.8 mM), which is compared with other dicopper catechol oxidase models.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
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Agrobacterium tumefaciens RNA in non-tumorous tomato cells 总被引:4,自引:0,他引:4
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Quantitative cytochemical studies of cortical parenchyma cells of roots of Pisum sativum in which the central vascular bundle is severed, showed esterase activity to be an early marker of the determination of cells to form a vascular bridge. Explantation, onto a basal culture medium, of wound segments taken from roots at different times after severing the stele showed the irreversibility of the esterase activity on removal from the inducing environment, so confirming this as a marker of cell determination. A general determination for the stele was shown to occur by 8–10 h after wounding, but information relating to tracheid secondary-cell-wall formation was not apparently available until 18–20 h after wounding. Determination appeared to occur well before mitosis. The timings of the differentiation steps indicate a simple diffusion model to explain the mechanism of arrival of the initiating molecules. 相似文献