Endoplasmic reticulum, concepts

In addition to microtubules, we have imaged other cellular structures, such as clathrin-coated pits, actin, nuclear pore complexes, endoplasmic reticulum, and mitochondria with STORM. The STORM imaging concept applies not... 

Proteins are synthesized on ribosomes as nascent polypeptides in the lumen of the endoplasmic reticulum (ER). The amino acid sequence of proteins that determines the secondary and tertiary structures is dictated by the nucleotide sequence of mRNA. In turn, mRNA sequences are determined by DNA sequences (Chapters 23-25). As discussed earlier, the classic experiments of Pauling and Anfinsen led to the concepts that certain key amino acids at the proper positions are essential for the folding of proteins into a three-dimensional, functional, unique conformation. It is amazing that, of hundreds of millions of conformational possibilities, only a single conformational form is... 

The traditional scientific approach to pharmaceutical safety assessment was based largely on the concept of xenobiotic-mediated direct injury to the whole animal, organ, tissue, or cell manifested by death altered function or modified growth rates. As scientific knowledge advanced, it became apparent that a variety of mechanisms were involved including direct injury to cellular macromolecules (e.g., DNA, RNA, proteins) or organelles (e.g., mitochondria, endoplasmic reticulum), adaptive responses (e.g., induction or inhibition of cyto-... 

Concept of necrosis has been considered such an accidental and uncontrolled process of cell death. Morphologically, necrotic cells exhibit swelling of organelles (such as endoplasmic reticulum and mitochondria ), permeabihzation of plasma membrane and consequent cellular lysis with a intact nucleus [86]. 

The discussion will lirst consider the chemical reaction catalyzed by y3-glucuronidase and will also deal with the function of /J-glucuronidase located either in the endoplasmic reticulum or in the lysosome of the cell. Tlie role of -glucuronidase in body fluid, especially intestinal contents and urine, will then be discussed. An interpretation follows of some of the phenomena discussed earlier in the chapter based on the concepts relating to the function of /3-gIucuronidase. 

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