Botrytis cinerea causes gray mold on a great number of host plants. Infection is initiated by airborne conidia that invade the host tissue, often by penetration of intact epidermal cells. To mimic the surface properties of natural plant surfaces, conidia were incubated on apple wax-coated surfaces, resulting in rapid germination and appressorium formation. Global changes in gene expression were analyzed by microarray hybridization between conidia incubated for 0 h (dormant), 1 h (pregermination), 2.5 h (postgermination), 4 h (appressoria), and 15 h (early mycelium). Considerable changes were observed, in particular between 0 h and 1 h. Genes induced during germination were enriched in those genes encoding secreted proteins, including lytic enzymes. Comparison of wild-type and a nonpathogenic MAP kinase mutant (bmp1) revealed marked differences in germination-related gene expression, in particular related to secretory proteins. Using promoter-GFP reporter strains, we detected a strictly germination-specific expression pattern of a putative chitin deacetylase gene (cda1). In contrast, a cutinase gene (cutB) was found to be expressed only in the presence of plant lipids, in a developmentally less stringent pattern. We also identified a coregulated gene cluster possibly involved in secondary metabolite synthesis which was found to be controlled by a transcription factor also encoded in this cluster. Our data demonstrate that early conidial development in B. cinerea is accompanied by rapid shifts in gene expression that prepare the fungus for germ tube outgrowth and host cell invasion.
The in vitro study of liver functions and liver cell specific responses to external stimuli deals with the problem to preserve the in vivo functions of primary hepatocytes. In this study, we used the biochip OrganoPlate TM (MIMETAS) that combines different advantages for the cultivation of hepatocytes in vitro: (1) the perfusion flow is achieved without a pump allowing easy handling and placement in the incubator; (2) the phaseguides allow plating of matrix-embedded cells in lanes adjacent to the perfusion flow without physical barrier; and (3) the matrix-embedding ensures indirect contact of the cells to the flow. In order to evaluate the applicability of this biochip for the study of hepatocyte's functions, Matrigel TM -embedded HepG2 cells were cultured over three weeks in this biochip and compared to a static Matrigel culture (3D) and a monolayer culture (2D). Chip-cultured cells grew in spheroid-like structures and were characterized by the formation of bile canaliculi and a high viability over 14 days. Hepatocyte-specific physiology was achieved as determined by an increase in albumin production. Improved detoxification metabolism was demonstrated by strongly increased cytochrome P450 activity and urea production. Additionally, chip-cultured cells displayed increased sensitivity to acetaminophen. Altogether, the OrganoPlate seems to be a very useful alternative for the cultivation of hepatocytes, as their behavior was strongly improved over 2D and static 3D cultures and the results were largely comparable and partly superior to the previous reports on biochip-cultured hepatocytes. As for the low technical needs, this platform has the appearance of being highly applicable for further studies of hepatocytes' responses to external stimuli. V C 2015 AIP Publishing LLC. [http://dx
Melatonin receptors mediate improvements of survival after polymicrobial sepsis in rats and mice; this effect appears to be independent from major alterations of cytokine release.
Rats are commonly used in medical research as they enable a high grade of standardization. The exhalome of ventilated rats has not as yet been investigated using an ion mobility spectrometer coupled with a multi-capillary column (MCC-IMS). As a first step, a rat model has to be established to measure potential biomarkers in the exhale with long-term settings, allowing constant and continuous analysis of exhaled air in time series. Therefore, eight animals were anaesthetized, prepared and ventilated for 1 h. A total of 73 peaks were directly detected with the IMS chromatogram. Thirty five of them were assigned to the ventilator system and 38 to the animals. Peak intensity varied within three measurements. The intensity of analytes of individual rats varied by a factor of up to 18. This new model will also enable continuous measurements of volatile organic compounds (VOCs) from rat's breath in long-term experiments. It is hoped that, in the future, variability and progression of VOCs can be monitored in different models of diseases using this set-up.
HepaRG is a bipotent stem cell line that can be differentiated towards hepatocyte-like and biliary-like cells. The entire cultivation process requires 1 month and relies on the addition of 2% dimethyl sulfoxide (DMSO) to the culture. Our motivation in this research is to differentiate HepaRG cells (progenitor cells and undifferentiated cells) towards hepatocyte-like cells by minimizing the cultivation time and without using DMSO treatment by instead using a microfluidic device combined with the following strategies: (a) comparison of extracellular matrices (matrigel and collagen I), (b) types of flow (one or both sides), and (c) effects of DMSO. Our results demonstrate that matrigel promotes the differentiation of progenitor cells towards hepatocytes and biliary-like cells. Moreover, the frequent formation of HepaRG cell clusters was observed by a supply of both sides of flow, and the cell viability and liver specific functions were influenced by DMSO. Finally, differentiated HepaRG progenitor cells cultured in a microfluidic device for 14 days without DMSO treatment yielded 70%of hepatocyte-like cells with a highly polarized organization that reacted to stimulation with IL-6 to produce C-reactive protein (CRP). This culture model has high potential for investigating cell differentiation and liver pathophysiology research.
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