Importance of replication

Lee Ml, Kuo FC, Whitmore GA, Sklar J. 2000. Importance of replication in microarray gene expression studies statistical methods and evidence from repetitive cDNA hybridizations. Proc Natl Acad Sci USA 97 9834. 

From this we can obtain a value which relates to how well die experiment obeys a linear model, often referred to as an error, or by some statisticians as a variance. However, this error is a simple number, which in the case discussed will probably be expressed in absorbance units (AU). Physical interpretation is not so easy. Consider an error that is reported as 100 mAU this looks large, but then express it as AU and it becomes 0.1. Is it now a large error The absolute value of die error must be compared with something, and here the importance of replication comes into play. It is useful to... 

What is the importance of replication, randomization, and local control in experimental design ... 

Field and Plant Tests Field exposure of test panels offers the benefit of a high degree of control over surface preparation and application. Moreover, through standardised exposure conditions, broader comparisons between both paint systems and locations are possible. More importantly, since replicates may be removed and laboratory tested periodically, changes in properties can be followed in considerable detail. At least four replicates should be examined for each exposure period to minimise the effects of atypical specimens. 

In that one individual, 5-HIAA level turned out to be 14 or 13. You might predict that he would have been the lowest one on the scale. I subsequently learned the importance of body height, and he happens to be a very short, stocky man. So we are now in the process of reanalyzing the data, trying to take in the appropriate variables into account. And, again, these arc studies that have to be replicated in our own hands and extended by others. 

We have discussed in a general way the nature of animal viruses in the first part of this chapter. Now we discuss in some detail the structure and molecular biology of a number of important animal viruses. Viruses will be discussed which illustrate different ways of replicating, and both RNA and DNA viruses will be covered. One group of animal viruses, those called the retroviruses, have both an RNA and a DNA phase of replication. Retroviruses are especially interesting not only because of their unusual mode of replication, but because retroviruses cause such important diseases as certain cancers and acquired immunodeficiency syndrome (AIDS). 

Before beginning our discussion of the manner of replication of animal viruses, we should mention first the important differences which exist between animal and bacterial cells. Since virus replication makes use of the biosynthetic machinery of the host, these differences in cellular organization and function imply differences in the way the viruses themselves replicate. 

The results obtained appeared quite promising, but the real sensation was the detection of pyruvate, the salt of 2-oxopropanoic acid (pyruvic acid), which is one of the most important substances in contemporary metabolism. Pyruvic acid was first obtained in 1835 by Berzelius from dry distillation of tartaric acid. The labile pyruvate was detected in a reaction mixture containing pure FeS, 1-nonanethiol and formic acid, using simulated hydrothermal conditions (523 K, 200 MPa). The pyruvate yield, 0.7%, was certainly not overwhelming, but still remarkable under the extreme conditions used, and its formation supports Wachtershauser s theory. Cody concludes from these results that life first evolved in a metabolic system prior to the development of replication processes. 

Fig. 10.8 The importance of the vesicle for the Darwinian evolution of a replicase. Compart-mentalisation ensures that related molecules tend to stay together. This permits superior mutant replicases (grey) to replicate more effectively than the parent (black) replicases. The evolutionary advantage spreads in the form of vesicles with superior replicase molecules, leading with a greater probability to vesicles with at least two replicase molecules (or a replicase and a matrix molecule). Vesicles with less than two replicase molecules are struck out their progeny cannot continue the RNA self-replication. Thus, the vesicles with better replicases form the growing fraction of vesicles which carry forward the replicase activity (Szostak et al., 2001)...

The importance of well-defined amounts of iron for the survival, replication and differentiation of the cells of animals, plants and almost all microorganisms (one... 

The chemical functioning of a cell is the main objective of Molecular Biology (MB). The isolation, identification, and purification of biomacromolecules could be seen as the first step, in fulfilling this objective. From the catalytic point of view, enzymes are the center of attention. However, the most important biomolecule in the cell is the DNA, in which the genetic code of each enzyme is enclosed, thus representing ultimate target for MB. The biochemical and molecular processes of replication, transcription, and translation become part of the objective. 

The nature of the target to be attacked by any drug obviously depends on the specific application. Many cytotoxic metal complexes target DNA because of its importance in replication and cell viability. Coordination compounds offer many binding modes to polynucleotides, including outer-sphere noncovalent binding, metal coordination to nucleobase and phosphate backbone... 

Hung, M., Patel, P., Davis, S., and Green, S. R. (1998). Importance of ribosomal frame-shifting for human immunodeficiency virus type 1 particle assembly and replication. J. Virol. 72, 4819-4824. 

The molecular basis by which interferons promote their characteristic effects, in particular antiviral activity, is understood at least in part. Interferon stimulation of the JAK-STAT pathway induces synthesis of at least 30 different gene products, many of which cooperate to inhibit viral replication. These antiviral gene products are generally enzymes, the most important of which are 2 -5 oligoadenylate synthetase (2,5-A synthetase) and the eIF-2a protein kinase. 

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