Replication reproduction

As with the D. magna tests, one of the problems has been in the successful formulation of a food to ensure the health and replicable reproduction of the C. dubia during the course of the toxicity tests. A combination of trout chow, yeast, rye grass powder, and algae have been used. Nonetheless, the C. dubia three-brood toxicity test has been proven to be useful and replicable. 

Replication Reproduction of a sample to obtain a measurable amount. 

A particularly interesting type of micellar catalysis is the autocatalytic self-replication of micelles [58]. Various examples have been described, but a particularly interesting case is the biphasic self-reproduction of aqueous caprylate micelles [59]. In this system ethyl caprylate undergoes hydroxyl catalysed hydrolysis to produce the free carboxylate anion, caprylate. Caprylate micelles then fonn. As these micelles fonn, they solubilize ethylcaprylate and catalyse further production of caprylate anion and caprylate micelles. 

Amino-5 -deoxy-2, 3 -0-isopropylideneadenosine was acylated at N-5 with an activated derivative of the 6-carboxy-2-naphthyl ester of Kemp s acid imide. The resulting molecule possesses self-complementary binding sites, the key feature of replicating molecules that act as templates for their own reproduction. The dimer of this molecule is, however, not very stable K = 630 L mol ). When the two initially mentioned educts are added, a small proportion of the ternary complex is also formed and undergoes a fast, template-catalysed... 

The double helix model provides a simple explanation for cell division and reproduction. In the reproduction process, the two DNA chains unwind from each other. As this happens, a new matching chain of DNA is synthesized on each of the original ones, creating two double helices. Since the base pairs in each new double helix must match in the same way as in the original, the two new double helices must be identical to the original. Exact replication of genetic data is thereby accomplished, however complex that data may be. 

Are the Data Reproducible If experimental results are to be accepted as meaningful by the scientific community, they must be capable of being reproduced by investigators in other laboratories as well as by the original investigator. An individual should assure this reproduction by replicating the experiment. 

Because viruses only replicate inside living cells, research on viruses requires use of appropriate hosts. For the study of bacterial viruses, pure cultures are used either in liquid or on semi-solid (agar) medium. Because bacteria are so easy to culture, it is quite easy to study bacterial viruses and this is why such detailed knowledge of bacterial virus reproduction is available. 

In this essay, I argue for a new perspective on units of evolutionary transition. I analyze the process of reproduction, which leads to a conception of units of evolution as reproducers. These units resolve to more familiar ideas of replicators or interactors at levels of spatial organization when explicit spatial and functional models are imposed on abstract reproducers. I also sketch a heuristically promising program of reductionistic research that flows from the new perspective. 

I offer a different and complementary perspective on units which accommodates developmental processes explicitly and which articulates the intimate relationship between units of hereditary transmission and developmental expression. I argue that a process perspective on the temporal dimension of the transition problem, focusing on the propagation of developmental capacities, is a helpful addition to the spatial and functional perspectives. Reproduction is the process that, in general, forms the basis for evolution at a level and also for evolutionary transition to new levels. Processes of inheritance and replication can be understood as special cases of reproduction. In order to formulate a view of how processes of development and hereditary propagation are intertwined in reproduction, let us consider development further. 

Progeneration plays, in some respects, the genealogical role of a concept of hereditary transmission or replication. However, unlike the Weisman-nist view of heredity and development as logically or empirically separable processes, I view progeneration as fundamentally intertwined with development. The aim of my analysis of reproduction is to articulate this intertwining. 

Reproduction is about the propagation of mechanisms of development. Because replication is a special case of inheritance and inheritance is a special case of reproduction, and because reproduction is the progeneration of mechanisms of development, it follows that if transmission genetics is a theory of replication, then transmission genetics is about development as well as about transmission. ... 

Instead of reproduction or replication , the more general term production was used. The third definition includes the first definition. However, because it contains neither Darwinian nor genetic specification, this definition takes both coded and uncoded life into account. Since the term population is not included, the definition can be applied to single objects such as robots. 

The information crisis , i.e., the fact that, because of the error frequency, longer RNA chains have so many errors after only a few reproduction steps that they can no longer be replicated, cries out for catalysts which can guarantee more exact replication. While only protein catalysts (enzymes) had been discussed until recently, ri-bozymes are now possible candidates. More complex catalysts would have required more complex matrices but where did the matrix molecules come from This serious problem, referred to by Eigen himself as an information crisis, is sometimes referred to as Eigen s dilemma (Blomberg, 1997). 

Fig. 8.4 Hypercycle phenomena can be observed when a cell is infected by an RNA virus. The vims provides the host cell with information for an enzyme favouring only the reproduction of viral information, i.e., of an RNA strand. This RNA is converted by the host cell into a protein (a replicase) which forms a new RNA minus-strand. The latter is then replicated to give a plus-strand (Eigen et al., 1982)...

The minimal cell, as the simplest system which has all the required properties of life (metabolism, self-reproduction and the ability to evolve), is presently studied as part of a new research discipline synthetic biology. This includes subjects such as synthesis in branches of biological systems, for example, of new RNA species, new peptides and new nucleic acid analogues, as well as the synthesis of peptide nucleic acids. One example is the work of M. R. Ghadiri and G. von Kiedrowski on self-replication of oligonucleotides and oligopeptides (Luisi, 2006b). 

The use of artificial cells for biotechnology applications is simplified if the replication and reproduction characteristics are removed so that an artificial cell does one particular job. A liposome structure would continue to uptake molecules from the environment and synthesise proteins or cofactors, but the molecular inventory within the liposome is comparatively small. 

Based on this concept of correlation between high replication rate/high persistent mutation risk, Pike et al. (1983) formulated the hypothesis of breast tissue age and developed a mathematical model to predict the effects of exposure to ovarian hormones. This model incorporates reproductive and endocrine items related to breast cancer and is able to predict the relative risk of individual situations with results that are very close to those observed in clinical trials. According to this hypothesis, both the years of exposure and the circulating serum levels of estrogens are associated to short-term breast cancer risk in postmenopausal women (Toniolo et al. 1995). 

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