Search results for "Microscopy"

Novel structural insights into F-actin-binding and novel functions of calponin homology domains.

2008

Tandem calponin homology (CH) domains are well-known actin filaments (F-actin) binding motifs. There has been a continuous debate about the details of CH domain-actin interaction, mainly because atomic level structures of F-actin are not available. A recent electron microscopy study has considerably advanced our structural understanding of CH domain:F-actin complex. On the contrary, it has recently also been shown that CH domains can bind other macromolecular systems: two CH domains from separate polypeptides Ncd80, Nuf2 can form a microtubule-binding site, as well as tandem CH domains in the EB1 dimer, while the single C-terminal CH domain of alpha-parvin has been observed to bind to a alp…

The Candida albicans cell wall-associated glyceraldehyde-3-phosphate dehydrogenase activity increases in response to starvation and temperature upshi…

2002

We have determined the effect of environmental factors (mild thermal upshift and starvation) on the Candida albicans cell wall-associated glyceraldehyde-3-phosphate dehydrogenase (cwGAPDH) activity. Temperature upshift (from 28 to 37 degrees C) and/ or starvation (at 28 or 37 degrees C in water) of exponentially growing yeast cells caused an increase in cwGAPDH activity (3 to 5-, and 7 to 8-fold, respectively). This increase in activity did not correlate with an increase in the amount of cwGAPDH protein present, as determined by flow cytometry, immunoelectron microscopy and Western-blotting. These results indicate that thermal upshift and starvation cause an activation of the cwGAPDH in C. …

Immunoelectron Microscopy of Hemocyanin from the Keyhole Limpet (Megathura crenulata): A Parallel Subunit Model

1993

Abstract Immunoelectron microscopy has been performed using negatively stained immune complexes of keyhole limpet hemocyanin (KLH) subunit 2 di- and multidecamers with domain-specific monoclonal antibodies. One antibody (KLH2 a macr 1) links the hemocyanin molecules in a side-to-side pattern, whereas the other antibody (KLH2 fg macr 1) links the molecules end-to-end. From existing knowledge of the domain sequence of KLH subunit 2, these data provide support for a parallel arrangement of subunits within each decamer. Ten N-terminal a macr: domains are then present at the noncollar region of each decamer with 10 C-terminal g macr domains at the collar region. The immunonegative staining data …

Comparison of epifluorescence microscopy and flow cytometry in counting freshwater picophytoplankton

2021

The smaller the phytoplankton, the greater effort is required to distinguish individual cells by optics-based methods. Flow cytometry is widely applied in marine picophytoplankton research, but in freshwater research its role has remained minor. We compared epifluorescence microscopy and flow cytometry in assessing the composition, abundance and cell sizes of autofluorescent picophytoplankton in epilimnia of 46 Finnish lakes. Phycocyaninrich picocyanobacteria were the most dominant. The two methods yielded comparable total picophytoplankton abundances, but the determination of cell sizes, and thus total biomasses, were on average an order of magnitude higher in the microscopy results. Howev…

Synthetic/ECM-inspired hybrid platform for hollow microcarriers with ROS-triggered nanoporation hallmarks

2017

Reactive oxygen species (ROS) are key pathological signals expressed in inflammatory diseases such as cancer, ischemic conditions and atherosclerosis. An ideal drug delivery system should not only be responsive to these signals but also should not elicit an unfavourable host response. This study presents an innovative platform for drug delivery where a natural/synthetic composite system composed of collagen type I and a synthesized polythioether, ensures a dual stimuli-responsive behaviour. Collagen type I is an extracellular matrix constituent protein, responsive to matrix metalloproteinases (MMP) cleavage per se. Polythioethers are stable synthetic polymers characterized by the presence o…

Aqueous foam as the carrier phase in the deposition of fibre networks

2015

Microspectroscopy and spectromicroscopy with photoemission electron microscopy using a new kind of imaging energy filter

2001

The use of an imaging retarding field analyser attached to the FOCUS IS-PEEM is described. This kind of energy filter is a simple, powerful tool to obtain microspectra from areas of down to about 1 μm using (V)UV and X-ray excitation sources. First results of microspectroscopy measured by excitation with a laboratory as well as a synchrotron X-ray source are presented.

Features extraction on complex images

2005

The accessibility of inexpensive and powerful computers has allowed true digital holography to be used for industrial inspection using microscopy. This technique allows the capture of a complex image (i.e., one containing magnitude and phase), and the reconstruction of the phase and magnitude information. Digital holograms give a new dimension to texture analysis, since the topology information can be used as an additional way to extract features. This new technique can be used to extend previous work on the image segmentation of patterned wafers for defect detection. The paper presents a comparison between the features obtained using Gabor filtering on complex images under illumination and…

Reconstruction Improvement in Integral Fourier Holography by Micro-Scanning Method

2015

Although integral holography has many promising advantages in the field of 3D imaging, the resolution of reconstructed holographic image is still limited by the insufficient information captured. To improve the reconstruction quality, an integral Fourier holographic imaging method based on micro-scanning of the micro-lens array is proposed in this paper. The micro-scanning of the micro-lens array can increase the sampling rate in spatial frequency domain and the information of the generated Fourier hologram, which will eventually eliminate the overlapping effect in the reconstructed 3D image. Experiments for different micro-scanning modes are carried out to verify the feasibility of the pro…

Pattern image enhancement by extended depth of field

2014

Abstract Most optical defect localization techniques such as dynamic laser stimulation or photon emission microscopy require a pattern image of the device to be taken. The main purpose is for device navigation, but it also enables the analyst to identify the location of the monitored activity by superimposing it onto the pattern image. The defect localization workflow usually starts at low or medium magnification. At these scales, several factors can lead to a lack of orthogonality of the sample with the optical axis of the system. Therefore, images can be locally out of focus and poorly resolved. In this paper, a method based on Depth of Field Extension is suggested to correct the pattern …