The Distribution of Coated Vesicles in Keratinizing Cells of the Wool Follicle

Orwin, D. F. G.; Thomson, R.W.

doi:10.1071/bi9720573

Cited by 8 publications

(1 citation statement)

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“…The biological membranes, such as the Golgi bodies, and structures like the desmosomes, were poorly visible in unfixed HPF-FS samples. However, the lack of Golgi bodies should not be confused as a lack of contrast with HPF and FS as the total number of Golgi bodies in this region is estimated to be approximately one per cell (Orwin & Thomson, 1972;Walther & Ziegler, 2002;Giddings, 2003). Lack of cell membrane visibility was proclaimed either due to extraction of lipids or to the failure of the bilayer membrane to bind electron-dense fixatives or stains.…”

Section: Preservation Of Key Aspects Of Follicle Biologymentioning

confidence: 99%

High‐pressure freezing followed by freeze substitution of a complex and variable density miniorgan: the wool follicle

Velamoor

Richena

Mitchell

et al. 2020

Journal of Microscopy

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Cryofixation by high-pressure freezing (HPF) followed by freeze substitution (FS) is a preferred method to prepare biological specimens for ultrastructural studies. It has been shown to achieve uniform vitrification and ultrastructure preservation of complex structures in different cell types. One limitation of HPF is the small sample volume of <200 µm thickness and about 2000 µm across. A wool follicle is a rare intact organ in a single sample about 200 µm thick. Within each follicle, specialized cells derived from multiple cell lineages assemble, mature and cornify to make a wool fibre, which contains 95% keratin and associated proteins. In addition to their complex structure, large density changes occur during wool fibre development. Limited water movement and accessibility of fixatives are some issues that negatively affect the preservation of the follicle ultrastructure via conventional chemical processing. Here, we show that HPF-FS of wool follicles can yield highquality tissue preservation for ultrastructural studies using transmission electron microscopy.

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Section: Preservation Of Key Aspects Of Follicle Biologymentioning

confidence: 99%

High‐pressure freezing followed by freeze substitution of a complex and variable density miniorgan: the wool follicle

Velamoor

Richena

Mitchell

et al. 2020

Journal of Microscopy

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Development of Hair Fibres

Harland

Plowman

2018

Advances in Experimental Medicine and Biology

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The growth of hairs occurs during the anagen phase of the follicle cycle. Hair growth begins with basement membrane-bound stem cells (mother cells) around the dermal papilla neck which continuously bud off daughter cells which further divide as a transient amplifying population. Division ceases as cell line differentiation begins, which entails changes in cell junctions, cell shape and position, and cell-line specific cytoplasmic expression of keratin and trichohyalin. As the differentiating cells migrate up the bulb, nuclear function ceases in cortex, cuticle and inner root sheath (IRS) layers. Past the top of the bulb, cell shape/position changes cease, and there is a period of keratin and keratin-associated protein (KAP) synthesis in fibre cell lines, with increases, in particular of KAP species. A gradual keratinization process begins in the cortex at this point and then non-keratin cell components are increasingly broken down. Terminal cornification, or hardening, is associated with water loss and precipitation of keratin. In the upper follicle, the hair, now in its mature form, detaches from the IRS, which is then extracted of material and becomes fragmented to release the fibre. Finally, the sebaceous and sudoriferous (if present) glands coat the fibre in lipid-rich material and the fibre emerges from the skin. This chapter follows the origin of the hair growth in the lower bulb and traces the development of the various cell lines.

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