Lipid membranes were assembled on polyelectrolyte (PE)-coated colloidal particles. The assembly was studied by means of confocal microscopy, flow cytometry, scanning force microscopy, and freeze-fracture electron microscopy. A homogeneous lipid coverage was established within the limits of optical resolution. Flow cytometry showed that the lipid coverage was uniform. Freeze-fracture electron microscopy revealed that the lipid was adsorbed as a bilayer, which closely followed the surface profile of the polyelectrolyte support. Additional adsorption of polyelectrolyte layers on top of the lipid bilayer introduced inhomogeneities as evident from jumps in the fracture plane. Characteristic lipid multilayers have not been seen with freeze-fracture electron microscopy.
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Life (Basel)
December 2024
Institute of Histology and Embryology, Faculty of Medicine, Comenius University in Bratislava, Špitálska Street 24, 813 72 Bratislava, Slovakia.
The human pineal gland is the largest producer of the hormone melatonin. Pineal acervuli (brain sand), calcified concretions in the pineal gland, have long been studied because of their association with ageing, melatonin production, and neurological disorders. The solid inorganic matter of the hydroxyapatite crystals often renders sample sectioning impossible, to the extent that the sections lose value.
View Article and Find Full Text PDFBio Protoc
December 2024
School of Bioengineering, Dalian University of Technology, Dalian, China.
Cryo-electron microscopy (cryo-EM) is a powerful technique capable of investigating samples in a hydrated state, compared to conventional high-vacuum electron microscopy that requires samples to be completely dry. During the drying process, numerous features and details may be lost due to damage caused by dehydration. Cryo-EM circumvents these problems by cryo-fixing the samples, thereby retaining the intact and original features of hydrated samples.
View Article and Find Full Text PDFUltrason Sonochem
December 2024
Research Centre for Natural Sciences, Institute of Materials and Environmental Chemistry, Magyar tudósok körútja 2, 1117 Budapest, Hungary.
Formation of unilamellae of fully hydrated dipalmitoylphosphatidylcholine (DPPC) was induced by a horn sonicator from multilamellar vesicles and followed by time-resolved synchrotron small angle X-ray scattering and direct visual morphological investigations by the means of transmission electron-microscopy combined with freeze-fracture. Without incubation the ultrasonication causes continuous increasing in temperature and transformation from the gel to rippled gel structures, then reaching the main transition, the formfactor of unilamellar structure appeared. The ultrasonication resulted in different layer formations at the characteristic temperatures of the gel (20 °C), rippled gel (38 °C), and liquid crystalline (45 °C) phases of the system.
View Article and Find Full Text PDFSci Adv
December 2024
Department of Biological Sciences, University of Rhode Island, Kingston, RI 02881, USA.
Similar to cellulose synthases (CESAs), cellulose synthase-like D (CSLD) proteins synthesize β-1,4-glucan in plants. CSLDs are important for tip growth and cytokinesis, but it was unknown whether they form membrane complexes in vivo or produce microfibrillar cellulose. We produced viable CESA-deficient mutants of the moss to investigate CSLD function without interfering CESA activity.
View Article and Find Full Text PDFJ Oleo Sci
December 2024
Faculty of Science and Technology, Tokyo University of Science.
An effective approach to stabilize emulsions is to increase the rigidity of oil-water (O/W) interfacial films by adsorbing molecular assemblies such as lamellar phases around the emulsion particles. In this study, we aimed to analyze the structure of a lamellar phase adsorbed at an O/W interface and to clarify the effect of the structure and physicochemical properties of the lamellar phase on the dispersion stability of emulsions. The adsorption of the lamellar phase at the O/W interface of the emulsions was confirmed by freeze-fracture transmission electron microscopy of O/W emulsions prepared by diluting and dispersing gels formed with polyglycerol fatty acid esters, water, and cetyl isooctanoate (CIO).
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