Macromolecular syntheses

R. N. MacDonald, Macromolecular Synthesis, Vol. 3, John Wiley Sons, Inc., New York, 1968. 

FIGURE 1.25 The virus life cycle. Viruses are mobile bits of genetic iuformatiou encapsulated in a protein coat. The genetic material can be either DNA or RNA. Once this genetic material gains entry to its host cell, it takes over the host machinery for macromolecular synthesis and subverts it to the synthesis of viral-specific nucleic acids and proteins. These virus components are then assembled into mature virus particles that are released from the cell. Often, this parasitic cycle of virus infection leads to cell death and disease. 

Matyjaszewski, K. Macromolecular engineering From rational design through precise macromolecular synthesis and processing to targeted macroscopic material properties. Prog. Polym. Sci., 30, 858, 2005. 

Raff The difference between macromolecular synthesis and degradation. Synthesis must be greater than degradation for the cell to grow. 

Virus infection obviously upsets the regulatory mechanisms of the host, since there is a marked overproduction of nucleic acid and protein in the infected cell. In some cases, virus infection causes a complete shutdown of host macromolecular synthesis while in other cases host synthesis proceeds concurrently with virus synthesis. In either case, the regulation of virus synthesis is under the control of the virus rather than the host. There are several elements of this control which are similar to the host regulatory mechanisms, but there are also some uniquely viral regulatory mechanisms. We discuss various regulatory mechanisms when we consider the individual viruses later in this chapter. 

The concept of repetitive growth with branching was first reported in 1978 by Vogtle [4] (University of Bonn, Germany) who applied it to the construction of low molecular weight amines. This was followed closely by the parallel and independent development of the divergent, macromolecular synthesis of true dendrimers in the Tomalia Group [5,6] (Dow Chemical Company). The first... 

Defensins Mammals, birds, Invertebrates, plants, fungi Membrane permeabilization, macromolecular synthesis inhibition Cell proliferation/differentiation chemotaxis induction of gene expression adaptive immune polarization in vivo protection cytokine/chemokine induction CCR6, TLRs -1, -2 and -4... 

Administered to mouse embryo cultures in vitro, trimethylamine was teratogenic, causing neural mbe defects and inhibiting embryonic growth. Trimethylamine may exert these effects by reducing macromolecular synthesis. Repeated intraperitoneal injections of trimethylamine hydrochloride in pregnant mice caused fetotoxicity only at maternally toxic doses. ... 

Huag T, Storm JF (2000) Protein kinase A mediates the modulation of the slow Ca2+-dependent K+ current, lsAHP,by the neuropeptides CRF, VIP, and CGRP in hippocampal pyramidal neurons. J Neurophysiol 83 2071-2079 Huang Y, Li X-C, Kandel ER (1994) cAMP contributes to mossy fiber LTP by initiating both a covalently mediated early phase and macromolecular synthesis-dependent late phase. Cell 79 69-79... 

Nguyen P, Kandel ER (1996) A macromolecular synthesis-dependent late phase oflong-term potentiation requiring cAMP in the medial perforant pathway of rat hippocampal slices. J Neurosci 16 3189-3198... 

Ciclopirox olamine is a synthetic broad-spectrum antimycotic agent with inhibitory activity against dermatophytes, Candida species, and P orbiculare. This agent appears to inhibit the uptake of precursors of macromolecular synthesis the site of action is probably the fungal cell membrane. 

Many studies on the cationic trypanocides have failed to identify their site(s) of action. A recent proposal is that their activity is due to interaction with biologically active polyamines, e.g. spermine and spermidine (80MI10809). These and other polyamines have significant roles in cell division and macromolecular synthesis. 

IV. NEW CATALYTIC SYSTEMS OF METAL COMPLEXES FOR MACROMOLECULAR SYNTHESIS... 

Nystrom, B. and Blanck, H. (1998) Effects of the sulfonylurea herbicide metsulfiiron methyl on growth and macromolecular synthesis in the green alga Selenastrum capricornutum, Aquatic Toxicology 43 (1), 25-39. 

Huang YY, Li XC, and Kandel ER (1994) cAMP contributes to mossy fiber LTP by initiating both a covalently mediated early phase and macromolecular synthesis-dependent late phase. Cell 79 69-79... 

Inhibition of macromolecular synthesis, mitochondrial energy metabolism, and reduction of DNA synthesis, as well as direct interaction with the cell membrane (increase in cytosolic Ca2+ concentration), have been implicated in organotin-induced cytotoxicity [169, 170]. Promotion of oxidative and DNA damage in vivo has been detected [171]. Oxidative damage and increased concentration of intracellular calcium ions seem to be the major factors contributing to triorga-notin-induced apoptosis in many cell lines [172]. 

Ornithine decarboxylase (ODC) is the first enzyme in the polyamine biosynthesis pathway. Polyamines play essential roles in cell proliferation and differentiation and participate in macromolecular synthesis. Inhibitors of ODC block aspects of tumor promotion and induce cellular differentiation in several animal carcinogenesis models. Thus induction of ODC has been implicated as being important to carcinogenesis, and ODC activity is an intermediate biomarker of cell proliferation in studies... 

Type I cells comprise 8-11% of the structural cells found in the alveolar region and yet cover 90-95% of the alveolar surface. Their major function is to allow gases to equilibrate across the air-blood barrier and to prevent leakage of fluids across the alveolar wall into the lumen. The type I epithelium is particularly sensitive to damage from a variety of inhaled toxicants due to their large surface area. Moreover, their repair capacity is limited because they have few organelles associated with energy production and macromolecular synthesis. 

The indirect method involves the preparation of a first block followed by a chemical change to introduce a reactive end-group. This reactive group allows the initation of the second growing-chain. In this case, the first block can be obtained by various routes of macromolecular synthesis polycondensation and ionic or radical polymerization. 

Cyclic siloxanes are very important monomers, both from the theoretical and the practical points of view. Organocyclosiloxanes were discovered and characterized by Kipping [52], The most frequently studied and practically applied organosilicon monomers are cyclie compounds of the type - Si(R,R2)—0]-nt. The homologues with n = 3—7 are the starting compounds for macromolecular synthesis and are the best known. Much larger cycles composed of 25 and more siloxane units have, however, been isolated... 

The monomer assumes several functions in the polymerizing medium. They are proportionately manifested in all the physical and chemical parameters of the polymerizing mixture. The monomers for macromolecular synthesis must be pure. The requirements concerning the permissible amount of impurities are ever more stringent this trend is uncompromising and unequivocal. 

Only a compound whose addition to the active centre proceeds virtually without side reactions can be a monomer for macromolecular synthesis it is very important that active centre inactivation does not occur. Other criteria are not so evident at first sight. 

Kobayashi and Saegusa published a review article about this kind of macromolecular synthesis [258], DA complexes remain at the centre of specialist interest [259] as do the corresponding processes of alternating polymer generation [260, 261 ]. 

Various groups of investigators so far do not agree in their ideas concerning the mechanism by which the polymer particles, swollen by monomer, are formed. To illustrate how the kinetics of a complicated macromolecular synthesis is being analyzed, the approach of the representatives of several laboratories will be presented. 

Guest, I., Varma, D.R. (1992). Teratogenic and macromolecular synthesis inhibitory effects of trimethylamine on mouse embryos in culture. J. Toxicol. Environ. Health 36 27-41. 

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