Tissue sieve

Cellector tissue sieves (Bellco Glass Company) 2 nesting sieves, upper one with 40 mesh to remove large contaminants, lower one with 150 mesh or finer to retain embryos... 

Soil (L, F, H, and A layers), mosses and fungal fruiting bodies were each collected from the same spots at the three locations. The L, F, H samples were ground to pass a 1 cm sieve the mineral soil was sieved to retain its fine-earth 2mm fraction mosses were separated into green versus dead tissues the fruiting bodies were separated by stalk and cap. Subsamples were freeze-dried prior to... 

Sloughing or disintegration of potatoes during cooking is a major attribute of texture that can be measured directly. In these tests the potato sample is cooked and sieved, and the mass of the remaining cooked potato tissue on the sieve is recorded (see for example Hejlova et al., 2006). 

Two complex tissues, the xylem and phloem, provide the conducting network or "circulatory system" of plants. In the xylem or woody tissue, most of the cells are dead and the thick-walled tubes (tracheids) serve to transport water and dissolved minerals from the roots to the stems and leaves. The phloem cells provide the principal means of downward conduction of foods from the leaves. Phloem cells are joined end to end by sieve plates, so-called because they are perforated by numerous minute pores through which cytoplasm of adjoining sieve cells appears to be connected by strands 5-9 pm in diameter.154 Mature sieve cells have no nuclei, but each sieve cell is paired with a nucleated "companion" cell. 

PORE. I A minute cavity in epidermal tissue as in skin, leaves, or leather, having a capillary channel to the surface that permits transport of water vapor from within outward but not the reverse. 2. A void of interstice between particles of a solid such as sand minerals or powdered metals, that permits passage of liquids or gases through the material in either direction. I11 some structures, such as gaseous diffusion barriers and molecular sieves, the pores ate of molecular dimensions, i.e 4-10 A units. Such microporous structures are useful for filtration and molecular separation purposes in various industrial operations. 3. A cell in a spongy structure made by gas formation (foamed plastic) that absorbs water on immersion but releases it when stressed. 

Such elements are readily obtained from low grade flour, which is sieved and the residue washed to free it completely from the small amount of adherent flour. Before observing this residue under the microscope, it is well to heat it to incipient boiling with a 10% solution of sodium carbonate, which dissolves the cell-contents of the tissues and renders more distinct the structure of the walls. 

Wash, hand-peel, chop and lyophilize each plant tissue material for 3-4 h at 25°C (e.g., soybean (Table 17.1), potato, banana, eggplant, sweet potato and artichoke (Table 17.2). Grind the dry tissue to obtain a fine powder and select the particle size using sieves of lower than 200 pm mesh. Store the dry powder in a desiccator at 25°C and use it as the enzymatic source of PPO or peroxidase in the preparation of biosensor. Determine enzymatic activity and total protein content as described in Procedure 22 (in CD accompanying this book). Prepare the carbon paste electrode with dry tissue as described in the same procedure. 

Figure 4.1 The mustard oil bomb in flower stalks of Arabidopsis thaliana consists of S-cells (with glucosinolates) and adjacent myrosin cells (with myrosinase). This is illustrated by transverse (A,C) and longitudinal (B) sections of a pedicel, analyzed by light microscopy (A,B) and transmission electron microscopy (C). The myrosin cells (m) are in contact with the S-cells (S-c), situated inside the starch sheath ( ) (A,B,C). The myrosin cells are located peripherally in the phloem tissue other cells of the phloem include sieve elements (s) and companion cells (cc, in (C) only).

Primary cultures of astrocytes are made from newborn rat cerebral cortex according to Dehouck et al. (1990). The meninges is cleaned off and the brain tissue is forced gently through a nylon sieve. DMEM supplemented with 10 % fetal calf serum, 2 mM glutamine, and 50 pg/ml of gentamicin is used for the dissociation of cerebral tissue and development of astrocytes. 

Hyaluronic acid is found in most connective tissues including human vitreous, skin, synovial fluid and umbilical cord. One of its biological roles is its ability to contain large amounts of water in intercellular space. It can thus locate cells in a jelly-like matrix and resistance of tissue towards infection may partly depend on this property. The intercellular matrix has a viscoelastic nature [75-77] and is thought to have a role in absorbing shock. Hyaluronic acid can exist in the form of aggregates [81,82] or a network structure [78-80], Such a network offers a filter or macromolecular sieve-like resistance to other molecules as well as cells [83,84],... 

Figure 1. Source leaf minor vein phloem. (A) Autoradiograph of leaf tissues following l C-sucrose accumulation showing radioactivity (white) in veins. (B) Tracing of an electron micrograph of a cross section of minor vein, x, xylem, vp, vascular parenchyma cc, companion cell se, sieve element pp, phloem parenchyma, me, mesophyll cell. Reproduced with permission from Ref. 6. Copyright 1983. Annual Reviews.

The development of selection technology is necessary in order to derive cell lines with specific traits, such as herbicide resistance, from tissue culture. Figure 9 depicts the somatic cell selection process using cell culture techniques. At the bottom left is a flask containing a suspension of alfalfa cells. These cells have been cultured for 4-8 weeks and then sieved to yield very small cell clumps which will be used for selection in vitro. 

Because sucrose has a mass of 0.342 kg mol-1, this flux density corresponds to (300 mol m-2 hour-1)(0.342 kg mol-1) or 100 kg m-2 hour-1. In the current example, the flow is per m2 of sieve-tube lumens the rate of flow per unit area of phloem tissue is less by the ratio of the lumen cross-sectional area to the total phloem cross-sectional area, which is usually 0.2 to 0.5. 

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