Protoplasms

Phosphorus is also an essential ingredient of all cell protoplasm, nervous tissue, and bones. 

Propylene oxide is a primary irritant, a mild protoplasmic poison, and a mild depressant of the central nervous system. Skin contact, even in dilute solution (1%), may cause irritation to the eyes, respiratory tract, and lungs. Propylene oxide is a suspected carcinogen in animals. The LC q (lowest lethal concentration by inhalation in tats) is 4000 mg/kg body weight. The LD q (oral) is 930 mg/kg. The LD q (dermal) is 1500 mg/kg. The TWA (8-h exposure) is 100 ppm and the STEP (15-min exposure) is 150 ppm. 

Structure of the Cell Wall. The iaterior stmcture of the ceU wall is shown in Figure 6. The interfiber region is the middle lamella (ML). This region, rich in lignin, is amorphous and shows no fibnUar stmcture when examined under the electron microscope. The cell wall is composed of stmcturaHy different layers or lamellae, reflecting the manner in which the cell forms. The newly formed cell contains protoplasm, from which cellulose and the other cell wall polymers are laid down to thicken the cell wall internally. Thus, there is a primary wall (P) and a secondary wall (S). The secondary wall is subdivided into three portions, the S, S2, and layers, which form sequentially toward the lumen. Viewed from the lumen, the cell wall frequendy has a bumpy appearance. This is called the warty layer and is composed of protoplasmic debris. The warty layer and exposed layer are sometimes referred to as the tertiary wad. 

Choline base [123-41 -17, [(CH2)3NCH2CH20H] 0H, triniethyl(2-hydroxyethyl)-ammonium hydroxide, derives its name from bile (Greek chole from which it was first obtained. This so-called free-ch oline is a colorless, hygroscopic Hquid with an odor of trimethyl amine. The quaternary ammonium compound (1) choline [62-49-7] or a precursor is needed in the diet as a constituent of certain phosphoHpids universally present in protoplasm. 

Metabolism All of the processes or chemical changes in an organism or a single cell by which food is built up (anabolism) into living protoplasm and by which protoplasm is broken down (catabolism) into simpler compounds with the exchange of energy. 

Cell The smallest structural unit of living matter capable of functioning independently it is a microscopic mass of protoplasm surrounded by a semipermeable membrane, including one or more nuclei and various non-living substances that are capable, either alone or with other cells, of performing all the fundamental functions of life. 

ProtokoU, n. minutes, record protocol. Protonen-bescbleunigung, /. acceleration of protons, -geseboss, n. proton projectile, -wandening, /. traveling of protons. Protoplasma-bewegung, /. protoplasmic motion. -kSrper, m. protoplasmic body, -strahl, m. protoplasmic ray. 

Ur-schleim, m. protoplasm, -schrift, /. original copy, original, -sprung, m. origin, source. 

Komnick, H., Stockem, W., Wohlfarth-Botterman, K.E. (1973). Cell motility Mechanisms in protoplasmic streaming and amoeboid movement. Int. Rev. Cytol. 34, 169-249. 

Lethal temperature thresholds of protoplasm in plant cells... 

CO2 + 16 HNO3 + H3PO4 + 122 H2O (Light) (CH2O)i06(NH3)i5(H3PO4) (Plankton protoplasm)... 

Fig. 10-13. The links between the cycling of C, N, and O2 are indicated. Total primary production is composed of two parts. The production driven by new nutrient input to the euphotic zone is called new production (Dugdale and Goering, 1967). New production is mainly in the form of the upward flux of nitrate from below but river and atmospheric input and nitrogen fixation (Karl et al, 1997) are other possible sources. Other forms of nitrogen such as nitrite, ammonia, and urea may also be important under certain situations. The "new" nitrate is used to produce plankton protoplasm and oxygen according to the RKR equation. Some of the plant material produced is respired in the euphotic zone due to the combined efforts...

Tazawa, M., Kishimoto, U. Kikuyama, M. (1974). Potassium, sodium and chloride in the protoplasm of Characea. Plant and Cell Physiology, 15, 103-10. 

The drying protoplast will be subjected to tension as the result of volume contraction and its adherence to the cell wall. Early observations (Steinbrick, 1900) on desiccation tolerant species showed that the protoplasm does not separate from the wall, but rather that it folds and cavities develop in the wall. Where there are thick-walled cells, localised separation of the plasmalemma from the wall may occur. It seems unlikely, however, that rupture of the plasmalemma normally occurs during desiccation. A more subtle form of membrane damage may arise from dehydration-induced conformational changes. Certainly it is relatively easy to demonstrate that dehydrated membranes exhibit a loss of functional integrity... 

Membranes are highly viscous, plastic structures. Plasma membranes form closed compartments around cellular protoplasm to separate one cell from another and thus permit cellular individuality. The plasma membrane has selective permeabilities and acts as a barrier, thereby maintaining differences in composition between the inside and outside of the cell. The selective permeabilities are provided mainly by channels and pumps for ions and substrates. The plasma membrane also exchanges material with the extracellular environment by exocytosis and endocytosis, and there are special areas of membrane strucmre—the gap junctions— through which adjacent cells exchange material. In addition, the plasma membrane plays key roles in cellcell interactions and in transmembrane signaling. 

As early as 1848, it had been suggested that sensory receptors transduce only one sensation, independent of the manner of stimulation. Behavioral experiments tend to support this theory. In 1919, Renqvist proposed that the initial reaction of taste stimulation takes place on the surface of the taste-cell membrane. The taste surfaces were regarded as colloidal dispersions in which the protoplasmic, sensory particles and their components were suspended in the liquor or solution to be tested. The taste sensation would then be due to adsorption of the substances in the solution, and equal degrees of sensation would correspond to adsorption of equal amounts. Therefore, the rate of adsorption of taste stimulants would be proportional to the total substances adsorbed. The phenomenon of taste differences between isomers was partly explained by the assumption that the mechanism of taste involves a three-dimensional arrangement for example, a layer of fatty acid floating on water would have its carboxylic groups anchored in the water whereas the long, hydrocarbon ends would project upwards. 

This group of drugs has often been classified as non-specific protoplasmic poisons and indeed such views are still expressed today. Such a broad generalization is, however, very far from the true position. 

Plants have a specific property, which is excitability [1-3]. This property is used by cells, tissues, and organs to change their internal condition and external reactions under the action of various environmental factors, referred to as irritants. The high sensitivity of protoplasm and all cell organelles to any natural and electrochemical effects is the basis for... 

If a section cut through a small sulfur-burned area of a lemon injured on the tree is examined microscopically, coagulation of protoplasm and cell collapse are apparent. Also, the injured tissue stains abnormally dark with safranin indicating the protoplasm has become more acidic than in normal tissue (18). Sides of the peel of lemons burned by sulfur on the tree were found to be higher in total sulfate than were uninjured sides of the same peel. The high total sulfate content of the peel was subsequently found to be due in part to soluble sulfate, as shown by analyses of the expressed cell solution (18). 

For anabolic reactions, which result in the production of new cells, it is important to know the approximate chemical composition of the biomass. The bacterial protoplasm comprises 75 to 80% water. The solid material is composed of several complex organic molecules, such as proteins, carbohydrates, and DNA. The mean composition of these molecules can be approximated by a relatively simple empirical formula, C60H87O23N12P, or in an even more simple form as C5H7O2N10.Numerous other elements such as sulfur, sodium, potassium, calcium, magnesium,... 

If we assume that those peculiarities of the toxin which cause their distribution are localized in a special group of the toxin molecules and the power of the organs and tissues to react with the toxin are localized in a special group of the protoplasm, we arrive at the basis of my side chain theory. The distributive groups of the toxin I call the haptophore group and the corresponding chemical organs of the protoplasm the receptor. . .. Toxic actions can only occur when receptors fitted to anchor the toxins are present. 

Clearly, the all-sulfur type ligand constitutes a very effective means of complexing both Fe11 and Fe111 in both aerobic and anaerobic protoplasm. 

Each cell consists primarily of a membrane, which separates it from the environment, preserves its structural integrity, and keeps it apart from other cells or from the surrounding environment. Plant cells, unlike animal cells, also have, in addition to a cell membrane, a cell wall, composed of cellulose and lignin. The cell wall provides structural strength not only to the vegetable cell itself but to all plant tissues as well. Inside the membrane, the interior of the cell, known as the protoplasm, includes two main... 

The above outline of the evolution of the plant kingdom during coal-forming eras has been presented largely in the language of botanical anatomy. However, the alert chemist will note that the anatomical differences imply considerable quantitative and spatial differences in the distribution of the principal plant constituents [cellulose, lignin, cutin, suberin and other waxes, contents of protoplasmic cells, pigments, resins, sporopollenin. 

The term protoplasm is used to indicate the thick viscous semifluid or almost jelly-like colorless, transparent material which makes up the essential substance of both the cell body and the nucleus, including the cytoplasmic membrane but not the cell wall. It contains a high percentage of water and holds fine granules in suspension. 

When the cell wall is damaged, the protoplasm usually disintegrates. However, methods are available for removing the cell membranes without destroying the vital nature of protoplasm. The term protoplast is used to indicate living protoplasm exclusive of the cell membranes. 

---