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51.
Lloyd J White Wim Declercq Frank Arfuso Adrian K Charles Arun M Dharmarajan 《Reproductive biology and endocrinology : RB&E》2009,7(1):98
Background
Within the human placenta, the cytotrophoblast consists of a proliferative pool of progenitor cells which differentiate to replenish the overlying continuous, multi-nucleated syncytiotrophoblast, which forms the barrier between the maternal and fetal tissues. Disruption to trophoblast differentiation and function may result in impaired fetal development and preeclampsia. Caspase-14 expression is limited to barrier forming tissues. It promotes keratinocyte differentiation by cleaving profilaggrin to stabilise keratin intermediate filaments, and indirectly providing hydration and UV protection. However its role in the trophoblast remains unexplored. 相似文献52.
Plant-parasitic nematodes are destructive plant pathogens that cause significant yield losses. They induce highly specialized feeding sites (NFS) in infected plant roots from which they withdraw nutrients. In order to establish these NFS, it is thought that the nematodes manipulate the molecular and physiological pathways of their hosts. Evidence is accumulating that the plant signalling molecule auxin is involved in the initiation and development of the feeding sites of sedentary plant-parasitic nematodes. Intercellular transport of auxin is essential for various aspects of plant growth and development. Here, we analysed the spatial and temporal expression of PIN auxin transporters during the early events of NFS establishment using promoter-GUS/GFP fusion lines. Additionally, single and double pin mutants were used in infection studies to analyse the role of the different PIN proteins during cyst nematode infection. Based on our results, we postulate a model in which PIN1-mediated auxin transport is needed to deliver auxin to the initial syncytial cell, whereas PIN3 and PIN4 distribute the accumulated auxin laterally and are involved in the radial expansion of the NFS. Our data demonstrate that cyst nematodes are able to hijack the auxin distribution network in order to facilitate the infection process. 相似文献
53.
Erin Quartley Andrei Alexandrov Maryann Mikucki Frederick S. Buckner Wim G. Hol George T. DeTitta Eric M. Phizicky Elizabeth J. Grayhack 《Journal of structural and functional genomics》2009,10(3):233-247
High level expression of many eukaryotic proteins for structural analysis is likely to require a eukaryotic host since many
proteins are either insoluble or lack essential post-translational modifications when expressed in E. coli. The well-studied eukaryote Saccharomyces cerevisiae possesses several attributes of a good expression host: it is simple and inexpensive to culture, has proven genetic tractability,
and has excellent recombinant DNA tools. We demonstrate here that this yeast exhibits three additional characteristics that
are desirable in a eukaryotic expression host. First, expression in yeast significantly improves the solubility of proteins
that are expressed but insoluble in E. coli. The expression and solubility of 83 Leishmania major ORFs were compared in S. cerevisiae and in E. coli, with the result that 42 of the 64 ORFs with good expression and poor solubility in E. coli are highly soluble in S. cerevisiae. Second, the yield and purity of heterologous proteins expressed in yeast is sufficient for structural analysis, as demonstrated
with both small scale purifications of 21 highly expressed proteins and large scale purifications of 2 proteins, which yield
highly homogeneous preparations. Third, protein expression can be improved by altering codon usage, based on the observation
that a codon-optimized construct of one ORF yields three-fold more protein. Thus, these results provide direct verification
that high level expression and purification of heterologous proteins in S. cerevisiae is feasible and likely to improve expression of proteins whose solubility in E. coli is poor. 相似文献
54.
Background
Most studies examining the commensal human oral microbiome are focused on disease or are limited in methodology. In order to diagnose and treat diseases at an early and reversible stage an in-depth definition of health is indispensible. The aim of this study therefore was to define the healthy oral microbiome using recent advances in sequencing technology (454 pyrosequencing). 相似文献55.
56.
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58.
Wim J. Vredenberg 《Photosynthesis research》2009,102(1):99-101
Quantitative data on laser flash-induced variable fluorescence in the 100 ns to 1 ms time range (Belyaeva et al. in Photosynth
Res 98:105–119, 2008) confirming those of others (Steffen et al. in Biochemistry 40:173–180, 2001, Biochemistry 44:3123–3132, 2005; Belyaeva et al. in Biophysics 51(6):976–990, 2006), need a substantial correction with respect to magnitude of the normalized variable fluorescence associated with single
turnover-induced charge separation in RCs of PS II. Their data are conclusive with the involvement of donor side quenching,
the release of which occurs with a rate constant in the range of tens of ms−1, and presumed to be associated with reduction of
Y\textz + Y_{\text{z}}^{ + } by the OEC. 相似文献
59.
Lactic acid bacteria as reducing and capping agent for the fast and efficient production of silver nanoparticles 总被引:1,自引:0,他引:1
Liesje Sintubin Wim De Windt Jan Dick Jan Mast David van der Ha Willy Verstraete Nico Boon 《Applied microbiology and biotechnology》2009,84(4):741-749
There is a growing demand for silver-based biocides, including both ionic silver forms and metallic nanosilver. The use of
metallic nanosilver, typically chemically produced, faces challenges including particle agglomeration, high costs, and upscaling
difficulties . Additionally, there exists a need for the development of a more eco-friendly production of nanosilver. In this
study, Gram-positive and Gram-negative bacteria were utilized in the non-enzymatic production of silver nanoparticles via
the interaction of silver ions and organic compounds present on the bacterial cell. Only lactic acid bacteria, Lactobacillus spp., Pediococcus pentosaceus, Enterococcus faecium, and Lactococcus garvieae, were able to reduce silver. The nanoparticles of the five best producing Lactobacillus spp. were examined more into detail with transmission electron microscopy. Particle localization inside the cell, the mean
particle size, and size distribution were species dependent, with Lactobacillus fermentum having the smallest mean particle size of 11.2 nm, the most narrow size distribution, and most nanoparticles associated with
the outside of the cells. Furthermore, influence of pH on the reduction process was investigated. With increasing pH, silver
recovery increased as well as the reduction rate as indicated by UV–VIS analyses. This study demonstrated that Lactobacillus spp. can be used for a rapid and efficient production of silver nanoparticles. 相似文献
60.