ORCID Profile
0000-0001-8869-709X
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Publisher: Springer Science and Business Media LLC
Date: 19-03-2013
DOI: 10.1038/NCOMMS2588
Abstract: The detection of small numbers of magnetic spins is a significant challenge in the life, physical and chemical sciences, especially when room temperature operation is required. Here we show that a proximal nitrogen-vacancy spin ensemble serves as a high precision sensing and imaging array. Monitoring its longitudinal relaxation enables sensing of freely diffusing, unperturbed magnetic ions and molecules in a microfluidic device without applying external magnetic fields. Multiplexed charge-coupled device acquisition and an optimized detection scheme permits direct spin noise imaging of magnetically labelled cellular structures under ambient conditions. Within 20 s we achieve spatial resolutions below 500 nm and experimental sensitivities down to 1,000 statistically polarized spins, of which only 32 ions contribute to a net magnetization. The results mark a major step towards versatile sub-cellular magnetic imaging and real-time spin sensing under physiological conditions providing a minimally invasive tool to monitor ion channels or haemoglobin trafficking inside live cells.
Publisher: Walter de Gruyter GmbH
Date: 18-05-2012
Abstract: Ongoing phytoplankton monitoring programs over the last 12 years in the northern Adriatic Sea showed that the diatom genus Bacteriastrum is an important component of the pelagic diatom assemblage. The main goals of this study were to identify which Bacteriastrum species occur in the northern Adriatic Sea and describe their distributions. Bacteriastrum comosum and B. hyalinum f. princeps were rare, while B. delicatulum , B. hyalinum , and B. mediterraneum were frequently present, together with the newly proposed species B. jadranum , described herein. This new species is weakly silicified and is mainly characterized by a large aperture between each cell of the filament. Cells are connected to each other by 8–12 setae, which cross at a distance equivalent to the diameters of 2–3 cells. There is no difference in the orientation of the setae on the two terminal cells, hence the species is placed in the section Isomorpha . The new species was recorded throughout the study area, in both coastal and offshore waters, with higher cell abundances in the vicinity of the Po River during the September–October period. The maximum cell abundance of B. jadranum was 244.2×10 3 cells l -1 in the surface waters at 44.75666667ºN, 12.75ºE in September 2006, sometimes representing up to 46% of the entire phytoplankton assemblage, as recorded in the surface waters at 45.06833333ºN, 13.515ºE in October 2008.
Publisher: Elsevier BV
Date: 07-2013
Publisher: Microbiology Society
Date: 2005
Abstract: Chlamydiae are a unique group of obligate intracellular bacteria comprising important pathogens of vertebrates as well as symbionts of free-living amoebae. Although there is le molecular evidence for a huge ersity and wide distribution of chlamydiae in nature, environmental chlamydiae are currently represented by only few isolates. This paper reports the recovery of a novel environmental chlamydia strain from activated sludge by co-cultivation with Acanthamoeba sp. The recovered environmental chlamydia strain UV-7 showed the characteristic morphology of chlamydial developmental stages as revealed by electron microscopy and was identified as a new member of the family Parachlamydiaceae (98·7 % 16S rRNA sequence similarity to Parachlamydia acanthamoebae ). Infection studies suggested that Parachlamydia sp. UV-7 is not confined to amoeba hosts but is also able to invade mammalian cells. These findings outline a new straightforward approach to retrieving environmental chlamydiae from nature without prior, tedious isolation and cultivation of their natural host cells, and lend further support to suggested implications of environmental chlamydiae for public health.
No related grants have been discovered for Michael Schweikert.