The Conjusome-A Transient Organelle Linking Genome Rearrangements in the Parental and Developing Macronuclei.

The conjusome plays an important role in the conjugation events that occur in . The conjusome appears in the anterior of conjugant pairs during the early stages of new macronuclei (anlagen) development. It lacks a membrane, and is composed of a network of fibrous, electron dense material, containing background cytoplasm and ribosomes.

Electric signals counterbalanced posterior vs anterior PTEN signaling in directed migration of Dictyostelium.

Background: Cells show directed migration response to electric signals, namely electrotaxis or galvanotaxis. PI3K and PTEN jointly play counterbalancing roles in this event via a bilateral regulation of PIP3 signaling. PI3K has been proved essential in anterior signaling of electrotaxing cells, whilst the role of PTEN remains elusive.

AKR1C3 mediates pan-AR antagonist resistance in castration-resistant prostate cancer.

Background: Antiandrogens are effective therapies that block androgen receptor (AR) transactivation and signaling in over 50% of castration-resistant prostate cancer (CRPC) patients. However, an estimated 30% of responders will develop resistance to these therapies within 2 years. JNJ-pan-AR is a broad-spectrum AR antagonist that inhibits wild-type AR as well as several mutated versions of AR that have emerged in patients on chronic antiandrogen treatment.

Disruption of microtubule function in cultured human cells by a cytotoxic ruthenium(ii) polypyridyl complex.

Treatment of malignant and non-malignant cultured human cell lines with a cytotoxic IC dose of ∼2 μM tris(4,7-diphenyl-1,10-phenanthroline)ruthenium(ii) chloride () retards or arrests microtubule motion as tracked by visualizing fluorescently-tagged microtubule plus end-tracking proteins. Immunofluorescent microscopic images of the microtubules in fixed cells show substantial changes to cellular microtubule network and to overall cell morphology upon treatment with . Flow cytometry with MCF7 and H358 cells reveals only minor elevations of the number of cells in G/M phase, suggesting that the observed cytotoxicity is not tied to mitotic arrest.

Live-cell imaging of small nucleolar RNA tagged with the broccoli aptamer in yeast.

The development of the RNA 'vegetable' aptamers, Spinach and Broccoli, has simplified RNA imaging, especially in live cells. These RNA aptamers interact with a fluorophore (DFHBI or DFHBI-1T) to produce a green fluorescence signal. Although used in mammalian and Escherichia coli cells, the use of these aptamers in yeast has been limited.

Real-time visualization of chromatin modification in isolated nuclei.

Chromatin modification is traditionally assessed in biochemical assays that provide average measurements of static events given that the analysis requires components from many cells. Microscopy can visualize single cells, but the cell body and organelles can hamper staining and visualization of the nucleus. Normally, chromatin is visualized by immunostaining a fixed sample or by expressing exogenous fluorescently tagged proteins in a live cell.

Recent advances in imaging subcellular processes.

Cell biology came about with the ability to first visualize cells. As microscopy techniques advanced, the early microscopists became the first cell biologists to observe the inner workings and subcellular structures that control life. This ability to see organelles within a cell provided scientists with the first understanding of how cells function.

A Worldwide Competition to Compare the Speed and Chemotactic Accuracy of Neutrophil-Like Cells.

Chemotaxis is the ability to migrate towards the source of chemical gradients. It underlies the ability of neutrophils and other immune cells to hone in on their targets and defend against invading pathogens. Given the importance of neutrophil migration to health and disease, it is crucial to understand the basic mechanisms controlling chemotaxis so that strategies can be developed to modulate cell migration in clinical settings.

On-chip open microfluidic devices for chemotaxis studies.

Microfluidic devices can provide unique control over both the chemoattractant gradient and the migration environment of the cells. Our work incorporates laser-machined micro and nanofluidic channels into bulk fused silica and cover slip-sized silica wafers. We have designed “open” chemotaxis devices that produce passive chemoattractant gradients without an external micropipette system.

Open access microfluidic device for the study of cell migration during chemotaxis.

Cells sense and interpret chemical gradients, and respond by localized responses that lead to directed migration. An open microfluidic device (OMD) was developed to provide quantitative information on both the gradient and morphological changes that occurred as cells crawled through various microfabricated channels. This device overcame problems that many current devices have been plagued with, such as complicated cell loading, media evaporation and channel blockage by air bubbles.

Directional sensing during chemotaxis.

Cells have the innate ability to sense and move towards a variety of chemoattractants. We investigate the pathways by which cells sense and respond to chemoattractant gradients. We focus on the model system Dictyostelium and compare our understanding of chemotaxis in this system with recent advances made using neutrophils and other mammalian cell types, which share many molecular components and signaling pathways with Dictyostelium.