Speeding up active mesh segmentation by local termination of nodes.

This article outlines a procedure for speeding up segmentation of images using active mesh systems. Active meshes and other deformable models are very popular in image segmentation due to their ability to capture weak or missing boundary information; however, where strong edges exist, computations are still done after mesh nodes have settled on the boundary. This can lead to extra computational time whilst the system continues to deform completed regions of the mesh. We propose a local termination procedure, reducing these unnecessary computations and speeding up segmentation time with minimal loss of quality

Speeding Up Active Mesh Segmentation by Local Termination of Nodes

This article outlines a procedure for speeding up segmentation of images using active mesh systems. Active meshes and other deformable models are very popular in image segmentation due to their ability to capture weak or missing boundary information; however, where strong edges exist, computations are still done after mesh nodes have settled on the boundary. This can lead to extra computational time whilst the system continues to deform completed regions of the mesh. We propose a local termination procedure, reducing these unnecessary computations and speeding up segmentation time with minimal loss of quality

Assessing Phototoxicity in a Mammalian Cell Line: How Low Levels of Blue Light Affect Motility in PC3 Cells.

Phototoxicity is a significant constraint for live cell fluorescence microscopy. Excessive excitation light intensities change the homeostasis of the observed cells. Erroneous and misleading conclusions may be the problematic consequence of observing such light-induced pathophysiology. In this study, we assess the effect of blue light, as commonly used for GFP and YFP excitation, on a motile mammalian cell line. Tracking PC3 cells at different light doses and intensities, we show how motility can be used to reliably assess subtle positive and negative effects of illumination. We further show that the effects are a factor of intensity rather than light dose. Mitotic delay was not a sensitive indicator of phototoxicity. For early detection of the effect of blue light, we analysed the expression of genes involved in oxidative stress. This study addresses the need for relatively simple and sensitive methods to establish a dose-response curve for phototoxicity in mammalian cell line models. We conclude with a working model for phototoxicity and recommendations for its assessment

Large‐scale quantification of stomatal patterning in barley leaves overexpressing epidermal patterning factor 1 reveals differential stomatal density between the adaxial and abaxial surfaces and spatial heterogeneity that impact stomatal function

Summary Stomatal density varies spatially over the leaf surface and between abaxial and adaxial leaf surfaces, with distribution greatly influencing plant photosynthesis and water use. However, methodological limitations have prevented quantification of spatial heterogeneity and its consequences for gaseous exchange in monocot crops. Here we introduce a simple and rapid method to image and quantify stomatal patterning over large (18 cm2) leaf areas in situ. We used this approach to assess spatial variation across the adaxial and abaxial surfaces in barley (Hordeum vulgare L.) wild‐type (WT) plants and mutants overexpressing the epidermal patterning factor 1 (EPF1). Analysing over a million stomata revealed significantly greater stomatal densities on the adaxial surface and towards the leaf tip in both genotypes. Overexpression of EPF1, however, differentially reduced stomatal densities on the two surfaces, while also increasing spatial variability, particularly on the abaxial surface, compared to WT. The uneven stomatal distribution proved crucial to separate simultaneous gas exchange measurements on the two surfaces, with impacts on both photosynthetic carbon gain and water use efficiency. Knowledge of the relationship between stomatal patterning and gaseous function is critical for the development of future crops with improved performance. </jats:p

Assessing Phototoxicity in a Mammalian Cell Line: How Low Levels of Blue Light Affect Motility in PC3 Cells

Phototoxicity is a significant constraint for live cell fluorescence microscopy. Excessive excitation light intensities change the homeostasis of the observed cells. Erroneous and misleading conclusions may be the problematic consequence of observing such light-induced pathophysiology. In this study, we assess the effect of blue light, as commonly used for GFP and YFP excitation, on a motile mammalian cell line. Tracking PC3 cells at different light doses and intensities, we show how motility can be used to reliably assess subtle positive and negative effects of illumination. We further show that the effects are a factor of intensity rather than light dose. Mitotic delay was not a sensitive indicator of phototoxicity. For early detection of the effect of blue light, we analysed the expression of genes involved in oxidative stress. This study addresses the need for relatively simple and sensitive methods to establish a dose-response curve for phototoxicity in mammalian cell line models. We conclude with a working model for phototoxicity and recommendations for its assessment.</jats:p

DataSheet1_Assessing Phototoxicity in a Mammalian Cell Line: How Low Levels of Blue Light Affect Motility in PC3 Cells.PDF

Phototoxicity is a significant constraint for live cell fluorescence microscopy. Excessive excitation light intensities change the homeostasis of the observed cells. Erroneous and misleading conclusions may be the problematic consequence of observing such light-induced pathophysiology. In this study, we assess the effect of blue light, as commonly used for GFP and YFP excitation, on a motile mammalian cell line. Tracking PC3 cells at different light doses and intensities, we show how motility can be used to reliably assess subtle positive and negative effects of illumination. We further show that the effects are a factor of intensity rather than light dose. Mitotic delay was not a sensitive indicator of phototoxicity. For early detection of the effect of blue light, we analysed the expression of genes involved in oxidative stress. This study addresses the need for relatively simple and sensitive methods to establish a dose-response curve for phototoxicity in mammalian cell line models. We conclude with a working model for phototoxicity and recommendations for its assessment.</p

Conserved phosphorylation of the Myosin1e TH1 domain impacts membrane association and function in yeast and worms.

Cells have an intrinsic ability to rapidly respond to environmental change to regulate cell cycle progression and membrane organisation, thereby regulating cell growth and division. The actin cytoskeleton is a highly dynamic complex of proteins which can rapidly reorganise to change the growth pattern of a cell. Class I myosins are monomeric actin associated motor proteins that play key roles in diverse cellular functions such as tension sensing and membrane reorganisation, as well as promoting actin polymer nucleation at sites of cell growth. We have analysed the localisation and function of both C. elegans class 1 myosins, HUM-1 (Myo1e) and HUM-5 (Myo1d). Both motors are non-essential. While HUM-1 is expressed in diverse cells and tissues, HUM-5 localises exclusively to a subset of cells in the nervous system. While animals lacking hum-1 displayed a reduced maximal brood size and a delay in embryo release, deleting both hum-1 and hum-5 together shortened C. elegans lifespan. Moreover, we identified that phosphorylation of a conserved serine residue within the Myo1e TH1 domain had any impact on the localisation and function of the motor protein in both C. elegans and the fission yeast, S. pombe, indicating this modification modulates the ability of Myo1e/HUM-1 to interact with phospholipids at the plasma membrane. We conclude that TH1 domain phosphorylation plays a key role in regulating the cellular distribution and function of Myo1e motors across all eukaryotes