Sub-cellular structure

Rodriguez EM, Gimenez AR. Zinc-iodide-osmium procedures as markers of sub-cellular structures. I. Standardization of staining of transmitter containing vesicles. Z mikrosk-anat Forsch 1981 95 257-275. 

Table 5.1 Distribution of PolyPs and other compounds between fractions of sub-cellular structures in 24 h mycelia of Neurospora crassa enriched in phosphorus (per 1.5 g of fresh weight) (Harold and Miller, 1961). 

Baatz, M. et al. 2006. Object-oriented image analysis for high content screening detailed quantification of cells and sub cellular structures with the Cellenger software. Cytometry A 69, 652-658. 

The majority of carotenoids tested in this study increased the rhodamine accumulation of the Colo 320 MDR/MRP human colon cancer cells by the inhibition of the MDR1-mediated efflux pump activity. The cell size and the intracellular or sub cellular structures of carotenoid-treated cells were not modified during the short period of the flow cytometric experiments. The mean fluorescence and the shift of the fluorescence peak increased to various extents in the presence of carotenoids. The most active compounds were antheraxanthin, violeoxanthin, apple peel phytox-anthin, lutein and violaxanthin, while the luteoxanthin, neoxanthin and /f-cryploxanlhin were only moderate in their inhibition of the efflux pump (Tables 7, 8). 

This section is concerned primarily with the effects of chemical modifications of keratins on their physical properties—supercontraction, setting, swelling, load-extension characteristics, and other mechanical properties. Much of this work could be described by the term mechanochemical coined by Speakman (1947). The complexity of the cellular and sub-cellular structure of keratins necessitates the use of simplifying assumptions in the interpretation of mechanochemical experiments. 

The limited resolution of fluorescence microscopy, however, leaves many biological structures too small to be observed in detail. The resolution of conventional light microscopy is limited by diffraction to 200-300 nm in the lateral directions and 500-800 nm in the axial direction, whereas sub-cellular structures span a range of length scales from nanometers to microns. Electron... 

Limonene. Use of fungal cultures which produce hydrolytic enzymes were used to increase the yield of endogenous products in citrus. Enzymatic digestion of plant cell wall structures or other sub-cellular structures enhances solubilization of these by-products. 

It is well known that various chemical agents can interfere with tubulin (which consists of a- and P-tubulins), and prevent it from combining effectively with microtubular-associated proteins to afford microtubules. The microtubules themselves are important sub-cellular structures involved in construction of the cytoskeleton, and in cell devision and cell movement. Representative chemicals which bind to tubulin are shown in Table 1. Most of these compounds are potent inhibitors of mitosis, and for this reason some of them appear to be promising chemotherapeutic agents in the treatment of certain cancers (e.g. breast and ovarian carcinomas). 

The approach of biochemical purification combined with high-resolution mass spectrometiy used for the definition of the PSP could be easily applied to many other sub-cellular structures. Indeed, subcellular structures, such as axo-glial junctions and nodes of Ranvier would be prime candidates for such an approach. Also, refined or new biochemical approaches to isolate structures such as dendrites, axons and growth cones would facilitate definition of other neuronal proteomes. 

Apart from the division of labour brought about by cell differentiation, and the grouping of similar cells into organs, a further division exists at the sub-cellular level. In this way, the many conflicting chemical reactions that take place simultaneously inside cells, achieve the required isolation in specialized compartments formed of selectively permeable membranes. The importance of these membranes is indicated by the fact that they comprise about 80% of the dry weight of an animal cell (O Brien, 1967). Our present understanding of sub-cellular structure stems from the adaptation of the electron microscope to this task by Albert Claude in 1940. 

Figure 9 Light absorption and scattering by microalgal cells. Scattering is the sum of reflection and refraction events of light rays by the (sub)cellular structures with different indices of refraction than that of the surrounding water.

In all the application examples presented here we did not discuss any methods and techniques for the measurements of light scattering parameters from cells, organelles and sub-cellular structures in general. This would be very useful in terms of defining the overall biomedical research and clinical context in which FDTD simulations could play a role, however, it was not part of our objectives. For a familiarization with some of the current progress in this field, the interested reader could refer to a recent publication by Boustany and Thakor [59] (and the references therein) as well as to some of the references included here [16-18]. 

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