Anomalous Features of EMT during Keratinocyte Transformation

During the evolution of epithelial cancers, cells often lose their characteristic features and acquire a mesenchymal phenotype, in a process known as epithelial-mesenchymal transition (EMT). In the present study we followed early stages of keratinocyte transformation by HPV16, and observed diverse cellular changes, associated with EMT. We compared primary keratinocytes with early and late passages of HF1 cells, a cell line of HPV16-transformed keratinocytes. We have previously shown that during the progression from the normal cells to early HF1 cells, immortalization is acquired, while in the progression to late HF1, cells become anchorage independent. We show here that during the transition from the normal state to late HF1 cells, there is a progressive reduction in cytokeratin expression, desmosome formation, adherens junctions and focal adhesions, ultimately leading to poorly adhesive phenotype, which is associated with anchorage-independence. Surprisingly, unlike “conventional EMT”, these changes are associated with reduced Rac1-dependent cell migration. We monitored reduced Rac1-dependent migration also in the cervical cancer cell line SiHa. Therefore we can conclude that up to the stage of tumor formation migratory activity is eliminated

Improving Novel Gene Discovery in High-Throughput Gene Expression Datasets

High-throughput gene expression datasets (including RNA-seq and microarray datasets) can quantify the expression level of tens of thousands of genes in an organism, which allows for the identification of putative functions for previously unstudied genes involved in treatment/condition responses. For static (single timepoint) high-throughput gene expression experiments, the most common first analysis step to discover novel genes is to filter out genes based on their degree of differential expression and the amount of inter-replicate noise. However, this filtering step may remove genes with very high baseline expression levels, and genes with important functional annotations in the experiment being studied. Chapter 2 presents a novel knowledge-based clustering approach for novel gene discovery, in which known functionally important genes as well as genes with very high expression levels (which would typically be removed by a strict fold change filter) are saved prior to filtering

A Link between Meiotic Prophase Progression and Crossover Control

During meiosis, most organisms ensure that homologous chromosomes undergo at least one exchange of DNA, or crossover, to link chromosomes together and accomplish proper segregation. How each chromosome receives a minimum of one crossover is unknown. During early meiosis in Caenorhabditis elegans and many other species, chromosomes adopt a polarized organization within the nucleus, which normally disappears upon completion of homolog synapsis. Mutations that impair synapsis even between a single pair of chromosomes in C. elegans delay this nuclear reorganization. We quantified this delay by developing a classification scheme for discrete stages of meiosis. Immunofluorescence localization of RAD-51 protein revealed that delayed meiotic cells also contained persistent recombination intermediates. Through genetic analysis, we found that this cytological delay in meiotic progression requires double-strand breaks and the function of the crossover-promoting heteroduplex HIM-14 (Msh4) and MSH-5. Failure of X chromosome synapsis also resulted in impaired crossover control on autosomes, which may result from greater numbers and persistence of recombination intermediates in the delayed nuclei. We conclude that maturation of recombination events on chromosomes promotes meiotic progression, and is coupled to the regulation of crossover number and placement. Our results have broad implications for the interpretation of meiotic mutants, as we have shown that asynapsis of a single chromosome pair can exert global effects on meiotic progression and recombination frequency

J Struct Biol

High-resolution imaging of hair-cell stereocilia of the inner ear has contributed substantially to our understanding of auditory and vestibular function. To provide three-dimensional views of the structure of stereocilia cytoskeleton and membranes, we developed a method for rapidly freezing unfixed stereocilia on electron microscopy grids, which allowed subsequent 3D imaging by electron cryo-tomography. Structures of stereocilia tips, shafts, and tapers were revealed, demonstrating that the actin paracrystal was not perfectly ordered. This sample-preparation and imaging procedure will allow for examination of structural features of stereocilia in a near-native state.R01 GM115972/NIGMS NIH HHS/National Institute of General Medical Sciences/United StatesP01 GM121203/NIGMS NIH HHS/National Institute of General Medical Sciences/United StatesP01 GM098412/NIGMS NIH HHS/National Institute of General Medical Sciences/United StatesP01 GM051487/NIGMS NIH HHS/National Institute of General Medical Sciences/United StatesP30 DC005983/NIDCD NIH HHS/National Institute on Deafness and Other Communication Disorders/United StatesR01 DC002368/NIDCD NIH HHS/National Institute on Deafness and Other Communication Disorders/United StatesR01 DC011034/NIDCD NIH HHS/National Institute on Deafness and Other Communication Disorders/United StatesS10 OD012372/ODCDC CDC HHS/Office of the Director/United States2020-05-01T00:00:00Z30822456PMC66843226542vault:3366

Measuring value creation in a virtual enterprise

This paper reviews the literature in relation to virtual organisations and e-readiness. From this, the authors develop an instrument to measure the readiness of the organisation to embrace the concepts of virtual work and collaboration. The instrument is applied in an aspiring virtual enterprise to identify the extent to which they are ready to create value through a virtual organising model

Synthetic Image Production for Digital Chest Tomosynthesis

The focus of this thesis is on the process of developing synthetic images from a digital chest tomosynthesis scan and evaluating the quality of the synthetic images for five patients using this process. Results demonstrate that the outlined PRIISM method is capable of producing intelligible synthetic chest images when compared to chest radiographs of the same body. The full-stack synthetic images possess high in-plane resolution with expected lacking depth resolution but often included numerous bright spots, low body coverage, and heightened bone presence. Slabbing the synthetic images removed most bright spots prominent in the full stack synthetic images and reduced rib bone presence over the lungs, but decreased the in-plane resolution and highly contrasted rib bones along the left and right edges of the lungs. Avenues for further evaluations of the quality of PRIISM, including ROC curve analysis and 3D simulation of the tomosynthesis data for viewing at various angular coverages, are discussed.Bachelor of Scienc

Managing organizational DSS development in small manufacturing enterprise

A number of Hong Kong manufacturing companies have moved their production to the People's Republic of China while retaining their supporting functions (such as marketing, distribution, etc.) in Hong Kong. As a consequence, their mode of operation has become more complex and demands better production planning and control (PPC). One solution is to use an information system in which all factory resources are integrated within a single framework for PPC. The main instrument of this strategy is an Organizational DSS (ODSS). This paper presents a case study of development and adoption of an ODSS in a small manufacturing enterprise. Analysis of the findings highlights the cultural as well as organizational underpinnings and the need for effective intervention before and throughout the computerization. The implementation strategies are described, with emphasis on prerequisite infrastructural developments, showing how they provide opportunities and constraints

Three-dimensional structure of basal body triplet revealed by electron cryo-tomography.

Basal bodies and centrioles play central roles in microtubule (MT)-organizing centres within many eukaryotes. They share a barrel-shaped cylindrical structure composed of nine MT triplet blades. Here, we report the structure of the basal body triplet at 33 Å resolution obtained by electron cryo-tomography and 3D subtomogram averaging. By fitting the atomic structure of tubulin into the EM density, we built a pseudo-atomic model of the tubulin protofilaments at the core of the triplet. The 3D density map reveals additional densities that represent non-tubulin proteins attached to the triplet, including a large inner circular structure in the basal body lumen, which functions as a scaffold to stabilize the entire basal body barrel. We found clear longitudinal structural variations along the basal body, suggesting a sequential and coordinated assembly mechanism. We propose a model in which δ-tubulin and other components participate in the assembly of the basal body