A Versatile Optical Clearing Protocol for Deep Tissue Imaging of Fluorescent Proteins in Arabidopsis thaliana.

Confocal microscopy is widely used to visualize gene expression patterns and developmental processes in plants. However, the imaging of plant tissue can be challenging due to its opacity, which often makes previous immersion in a clearing agent necessary. Many commonly-used chemicals suffer either from their incompatibility with fluorescent proteins or their complex and lengthy application.

Advanced light microscopy core facilities: Balancing service, science and career.

Core Facilities (CF) for advanced light microscopy (ALM) have become indispensable support units for research in the life sciences. Their organizational structure and technical characteristics are quite diverse, although the tasks they pursue and the services they offer are similar. Therefore, throughout Europe, scientists from ALM-CFs are forming networks to promote interactions and discuss best practice models.

Whole-body gene expression pattern registration in Platynereis larvae.

Background: Digital anatomical atlases are increasingly used in order to depict different gene expression patterns and neuronal morphologies within a standardized reference template. In evo-devo, a discipline in which the comparison of gene expression patterns is a widely used approach, such standardized anatomical atlases would allow a more rigorous assessment of the conservation of and changes in gene expression patterns during micro- and macroevolutionary time scales. Due to its small size and invariant early development, the annelid Platynereis dumerilii is particularly well suited for such studies.

Microglial repopulation model reveals a robust homeostatic process for replacing CNS myeloid cells.

Under most physiological circumstances, monocytes are excluded from parenchymal CNS tissues. When widespread monocyte entry occurs, their numbers decrease shortly after engraftment in the presence of microglia. However, some disease processes lead to focal and selective loss, or dysfunction, of microglia, and microglial senescence typifies the aged brain.

Spectral discrimination of cerebral amyloid lesions after peripheral application of luminescent conjugated oligothiophenes.

In vivo imaging of pathological protein aggregates provides essential knowledge of the kinetics and implications of these lesions in the progression of proteopathies, such as Alzheimer disease. Luminescent conjugated oligothiophenes are amyloid-specific ligands that bind and spectrally distinguish different types of amyloid aggregates. Herein, we report that heptamer formyl thiophene acetic acid (hFTAA) passes the blood-brain barrier after systemic administration and specifically binds to extracellular β-amyloid deposits in the brain parenchyma (Aβ plaques) and in the vasculature (cerebral β-amyloid angiopathy) of β-amyloid precursor protein transgenic APP23 mice.

Repeatable target localization for long-term in vivo imaging of mice with 2-photon microscopy.

Repetitive in vivo imaging in mice has become an indispensable tool for studying dynamic changes in structure and function of the brain. We describe a head fixation system, which allows rapid re-localization of previously imaged regions of interest (ROIs) within the brain. Such ROIs can be automatically relocated and imaged over weeks to months with negligible rotational change and only minor translational errors.

Primary human CD4+ T cells have diverse levels of membrane lipid order that correlate with their function.

Membrane lipid microdomains (lipid rafts) play an important role in T cell function by forming areas of high lipid order that facilitate activation. However, their role in regulating T cell differentiation and function remains controversial. In this study, by applying a new approach involving microscopy and flow cytometry, we characterize membrane lipid order in ex vivo primary human CD4(+) T cells.

Long-term in vivo imaging of β-amyloid plaque appearance and growth in a mouse model of cerebral β-amyloidosis.

Extracellular deposition of the amyloid-β peptide (Aβ) in the brain parenchyma is a hallmark lesion of Alzheimer's disease (AD) and a predictive marker for the progression of preclinical to symptomatic AD. Here, we used multiphoton in vivo imaging to study Aβ plaque formation in the brains of 3- to 4-month-old APPPS1 transgenic mice over a period of 6 months. A novel head fixation system provided robust and efficient long-term tracking of single plaques over time.

Engrailed-2 regulates genes related to vesicle formation and transport in cerebellar Purkinje cells.

Engrailed transcription factors regulate survival, cell fate decisions and axon pathfinding in central neurons. En-2 can also attenuate Purkinje cell (PC) maturation. Here, we use array analysis to scrutinize gene expression in developing PCs overexpressing Engrailed-2 (L7En-2).

Engrailed-2 negatively regulates the onset of perinatal Purkinje cell differentiation.

The transcription factor Engrailed-2 is expressed in cerebellar Purkinje cells (PCs) throughout embryonic development but is downregulated in PCs after birth. Since the onset of PC differentiation coincides with this change of gene expression, we asked whether downregulation of Engrailed-2 is necessary for proper timing of PC differentiation. To investigate this, we used an L7En-2 transgenic mouse model in which Engrailed-2 expression in PCs is maintained beyond the day of birth.