Fluorescent in situ hybridization with a 16S rRNA probe specific for Verrucomicrobia was used to (i) confirm the division-level identity of and (ii) study the behavior of the obligate intracellular verrucomicrobium "Candidatus Xiphinematobacter" in its nematode hosts. Endosymbionts in the egg move to the pole where the gut primordium arises; hence, they populate the intestinal epithelia of juvenile worms. During the host's molt to adult female, the endosymbionts concentrate around the developing ovaries to occupy the ovarian wall. Some bacteria are enclosed in the ripening oocytes for vertical transmission. Verrucomicrobia in males stay outside the testes because the tiny spermatozoids are not suitable for transmission of cytoplasmic bacteria.

We present Nikon-TRACKFlow, a new system with dedicated modules for automated microscope control and imaging for the fission track laboratory. It serves as a Nikon alternative for the Zeiss-based TrackWorks package from Autoscan Systems. Nikon-TRACKFlow is based on the Nikon Eclipse Ni-E motorised upright microscope and is embedded within Nikon NIS-Elements software. The system decouples image acquisition from analysis to decrease schedule stress of the microscope based on a number of automated user-friendly designs and protocols: (1) the well plate design that allows sequential scanning of multiple samples without the need of replacing the slide on the stage; (2) two protocols that are designed for the external detector method and the LA-ICP-MS fission track approach with tools for repositioning and calibration of the external detector; and (3) two other tools that are designed for automated point selection and scanning of large crystals, such as the Durango age standard and U-doped glass external detectors. In future versions, Nikon-TRACKFlow aims to step away from the dedicated system for fission track imaging towards a general high-throughput imaging system for Earth Sciences and other material-oriented sciences.

We investigated the effects of environmental pollution on genetic damage in wood mice (Apodemus sylvaticus) by means of the comet assay, with special attention to the role of age and gender as potential confounding variables. The present study was carried out at four sites along a pollution gradient in the vicinity of Antwerp (Belgium), with a nonferrous smelter as the main pollution source. We measured the concentration of heavy metals (Cd, Co, Cr, Cu, Fe, Mn, Pb, and Zn) in mouse liver and kidney and the concentration of organochlorine compounds (polychlorinated biphenyls and 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene) in mouse muscle tissue to assess individual exposure. Cadmium exposure was very high at the sites closest to the smelter, and exposure to this metal decreased with increasing distance from the smelter. Exposure to the other pollutants was low to moderate at the different sites. Genetic damage was higher in mice from populations in the vicinity of the nonferrous smelter compared with that in the control populations. A significant increase in genetic damage with age was observed at the most polluted sites, but not at the control sites. Genetic damage was higher in male mice than in female mice at the most polluted site, but not at the other areas. Yet, no obvious relationship was found between individual pollutant levels and individual genetic damage levels. We conclude that the comet assay can be used to compare genotoxicity at the population level if the confounding variables of gender and age are taken into account. However, its use for individual health risk assessment remains questionable.

<p><strong>Abstract.</strong> We here present TRACK<i>Flow</i>, a new system with dedicated modules for the fission track (FT) laboratory. It is based on the motorised Nikon Eclipse Ni-E upright microscope with the Nikon DS-Ri2 full frame camera and is embedded within the Nikon NIS-Elements Advanced Research software package. TRACK<i>Flow</i> decouples image acquisition from analysis to decrease schedule stress of the microscope. The system further has the aim of being versatile, adaptable to multiple preparation protocols and analysis approaches. It is both suited for small-scale laboratories and is also ready for upscaling to high-throughput imaging. The versatility of the system, based on the operators’ full access to the NIS-Elements package, exceeds that of other systems for FT and further expands to stepping away from the dedicated FT microscope towards a general microscope for Earth Sciences, <i>including</i> dedicated modules for FT research. </p> <p> TRACK<i>Flow</i> consists of a number of user-friendly protocols which are based on the well plate design that allows sequential scanning of multiple samples without the need of replacing the slide on the stage. All protocols include a sub-protocol to scan a map of the mount for easy navigation through the samples on the stage. Two protocols are designed for the External Detector Method (EDM) and the LA–ICP–MS apatite fission track (LAFT) approach, with tools for repositioning and calibration to the external detector. Two other tools are designed for large crystals, such as the Durango age standard and U-doped glass external detectors. These protocols generate a regular grid of points and inspect if each point is suitable for analysis. Both protocols also include an option to image each withheld point. One more protocol is included for the measurement of etch pit diameters and one last protocol prepares a list of coordinates for correlative microscopy. In a following phase of development TRACK<i>Flow</i> can be expanded towards fully autonomous calibration, grain detection and imaging.</p>

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