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Gang Li Tianming Liu Ashley Tarokh Jingxin Nie Lei Guo Andrew Mara Scott Holley Stephen TC Wong 《BMC cell biology》2007,8(1):40
Background
Reliable segmentation of cell nuclei from three dimensional (3D) microscopic images is an important task in many biological studies. We present a novel, fully automated method for the segmentation of cell nuclei from 3D microscopic images. It was designed specifically to segment nuclei in images where the nuclei are closely juxtaposed or touching each other. The segmentation approach has three stages: 1) a gradient diffusion procedure, 2) gradient flow tracking and grouping, and 3) local adaptive thresholding. 相似文献22.
Background
Automated identification of cell cycle phases of individual live cells in a large population captured via automated fluorescence microscopy technique is important for cancer drug discovery and cell cycle studies. Time-lapse fluorescence microscopy images provide an important method to study the cell cycle process under different conditions of perturbation. Existing methods are limited in dealing with such time-lapse data sets while manual analysis is not feasible. This paper presents statistical data analysis and statistical pattern recognition to perform this task. 相似文献23.
Hong Zhao Jinmin Zhu Kemi Cui Xiaoyin Xu Megan O'Brien Kelvin K Wong Santosh Kesari Weiming Xia Stephen TC Wong 《Cancer cell international》2009,9(1):15
Background
Cancer and Alzheimer's disease (AD) are two seemingly distinct diseases and rarely occur simultaneously in patients. To explore molecular determinants differentiating pathogenic routes towards AD or cancer, we investigate the role of amyloid β protein (Aβ) on multiple tumor cell lines that are stably expressing luciferase (human glioblastoma U87; human breast adenocarcinoma MDA-MB231; and mouse melanoma B16F). 相似文献24.
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Tobamoviruses, mostly isolated from solanaceous plants, may represent
ancient virus lineages that have codiverged with their hosts. Recently
completed nucleotide sequences of six nonsolanaceous tobamoviruses allowed
assessment of the codivergence hypothesis and support a third subgroup
within tobamoviruses. The genomic sequences of 12 tobamoviruses and the
partial sequences of 11 others have been analyzed. Comparisons of the
predicted protein sequences revealed three clusters of tobamoviruses,
corresponding to those infecting solanaceous species (subgroup 1), those
infecting cucurbits and legumes (subgroup 2), and those infecting
crucifers. The orchid-infecting odontoglossum ringspot tobamovirus was
associated with subgroup 1 genomes by its coat and movement protein
sequences, but with the crucifer-pathogenic tobamoviruses by the remainder
of its genome, suggesting that it is the progeny of a recombinant. For four
of five genomic regions, subgroup 1 and 3 genomes were equidistant from a
subgroup 2 genome chosen for comparison, suggesting uniform rates of
evolution. A phylogenetic tree of plant families based on the tobamoviruses
they harbor was congruent with that based on rubisco sequences but had a
different root, suggesting that codivergence was tempered by rare events of
viruses of one family colonizing another family. The proposed subgroup 3
viruses probably have an origin of virion assembly in the movement protein
gene, a large (25-codon) overlap of movement and coat protein open reading
frames, and a comparably shorter genome. Codon-position- dependent base
compositions and codon prevalences suggested that the coat protein frame of
the overlap region was ancestral. Bootstrapped parsimony analysis of the
nucleotides in the overlap region and of the sequences translated from the
-1 frame (the subgroup 3 movement protein frame) of this region produced
trees inconsistent with those deduced from other regions. The results are
consistent with a model in which a no or short overlap organization was
ancestral. Despite encoding of subgroup 2 and 3 movement protein C-termini
by nonhomologous nucleotides, weak similarities between their amino acid
sequences suggested convergent sequence evolution.
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Methylmethacrylate (MMA) is the most commonly used embedding medium for sectioning undecalcified bone; however, a number of problems exist with its use in a research laboratory. MMA requires a long infiltration time and temperature control, and it reacts with many polymers. We used Kleer Set resin™ as an alternative embedding medium for sectioning undecalcified bone specimens. Fluorochrome labeled bone specimens were sectioned transversely using a ground section technique and longitudinally on a sledge macrotome. The slides were viewed using both transmitted light and epifluorescence microscopy. High quality sections were obtained using Kleer Set resin™ for both sectioning techniques. We have shown that this new embedding medium is simpler, safer, quicker to use and does not interfere with visualization of fluorochromes. 相似文献