Principal component-based image segmentation: a new approach to outline in vitro cell colonies

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Real-time bacterial microcolony counting using on-chip microscopy

Observing microbial colonies is the standard method for determining the microbe titer and investigating the behaviors of microbes. Here, we report an automated, real-time bacterial microcolony-counting system implemented on a wide field-of-view (FOV), on-chip microscopy platform, termed ePetri. Using sub-pixel sweeping microscopy (SPSM) with a super-resolution algorithm, this system offers the ability to dynamically track individual bacterial microcolonies over a wide FOV of 5.7 mm × 4.3 mm without requiring a moving stage or lens. As a demonstration, we obtained high-resolution time-series images of S. epidermidis at 20-min intervals. We implemented an image-processing algorithm to analyze the spatiotemporal distribution of microcolonies, the development of which could be observed from a single bacterial cell. Test bacterial colonies with a minimum diameter of 20 μm could be enumerated within 6 h. We showed that our approach not only provides results that are comparable to conventional colony-counting assays but also can be used to monitor the dynamics of colony formation and growth. This microcolony-counting system using on-chip microscopy represents a new platform that substantially reduces the detection time for bacterial colony counting. It uses chip-scale image acquisition and is a simple and compact solution for the automation of colony-counting assays and microbe behavior analysis with applications in antibacterial drug discovery

Unified framework for counting agriculture-related objects in digital images.

Abstract-Counting objects is an important activity in the daily routine of many areas of industry. This is particularly true in agriculture, in which objects like cells, microorganisms, seeds and other structures have to be quantified as a source of relevant information. This paper proposes a framework that aggregates three different algorithms into a single tool able to tackle a wide variety of counting problems that exist in the agriculture industry. The factor that brings all those algorithms together is the input by the user of some templates for the objects, which allows the resulting method to select the best option for those particular conditions. As a desirable side effect, problems related to resolution and scale dependencies that plagued those previous algorithms are mostly solved by this new approach.SIBGRAPI 2012

Exploring mechanisms of drug resistance in multiple myeloma: the roles of the progenitor compartment, APRIL and Notch signalling

Multiple myeloma (MM) is characterised by the proliferation of clonal plasma cells and a number of novel, highly effective anti-MM agents have improved long-term survival. However, eventually all patients become resistant and the disease remains incurable. The occurrence of disease relapse after the apparent eradication of the clonal population indicates the persistent survival of a drug resistant, ‘progenitor’ subpopulation. Understanding the mechanisms that underlie these patterns of resistance, including the characterisation of MM progenitors, is therefore critical to improving clinical outcomes. A cancer stem cell model has been proposed in the context of MM, based on the lack of syndecan-1 (CD138) in clonal, light chainrestricted cells. This work did not substantiate this claim, and data from a series of primary samples suggest that lack of CD138 is not a robust marker for a progenitor population of MM cells. The bone marrow (BM) microenvironment is known to play a critical part in MM cell survival and resistance, mediated by cytokines present within MM cell niches, and by cell-contact dependent pathways activated in MM cells and within adjacent supportive BM cells. This work examines the role of A Proliferation-Inducing Ligand (APRIL), and of the Notch signalling pathway. The data suggest that soluble APRIL confers protection against Dexamethasone-induced apoptosis, whilst the Notch ligand Delta-like ligand-1, expressed on the stromal cell line, HS-5, enhances stroma-mediated protection against bortezomib