Mutant effects

Krek, W., Marks, J., Schmitz, N Nigg, E. A., and Simanis, V. (1992). Vertebrate p34c 2 phosphorylation site mutants effects upon cell cycle progression in the fission yeast Schizosaccammyces pombe. J. Cell Sci. 102 43-53. 

Antibiotic producing wild type had competitive advantage over mutant. Effect more profound in unplanted soil than rhizosphere. 

From 0 to 12 days post-pollination (DPP), little or no detectable differences are observed between normal and these mutants (except su) with respect to kernel and amyloplast development. The various mutant effects thus become expressed after 12 DPP during the major period of starch accumulation. The mutant su differs from normal and the other mutants by initially producing compound granules.44,161... 

By using mutants of maize and other species, progress has been made in understanding the pathways and enzymes involved in starch biosynthesis and the fine structure of starch polysaccharides. However, starch biosynthesis (Chapter 4) and granule formation are still not completely understood. Thus, integration of the information on polysaccharide biosynthesis (Section 3.6) with that on mutant effects (Section 3.7), is necessary to fully understand polysaccharide biosynthesis and to delineate the limits of this knowledge. 

Table 3.9 Summary of mutant effects in maize where an associated enzyme lesion has been reported...

Mean-field theory can be used to predict the effects of mutation rate and parent fitness on the moments of the mutant fitness distribution (Voigt et al, 2000a). In this analysis, only the portion of the mutant distribution that is not dead (zero fitness) or parent (unmutated) is considered. The mutant effects are averaged over the transition probabilities without the cases of mutations to stop codons or when no mutations are made on a sequence. In order to obtain the fitness distribution, two probabilities are required (1) the probability pi(a) that a particular amino-acid identity a exists at a residue i, and (2) the transition probability that one amino acid will mutate into another Q = 1 — (1 — pm)3. The probability vectors p a) can be determined through a mean-held approach (Lee, 1994 Koehl and Delarue, 1996 Saven and Wolynes, 1997). The amino acid transition probabilities Q are calculated based on the special connectivity of the genetic code and the per-nucleotide mutation rate. Removing transitions to stop codons and unmutated sequences only requires the proper normalization of the probabilities pi and the moments. For example, the first moment of the fitness improvement w of the uncoupled fitness function is written as... 

It is reported that a purine-requiring mutant of Escherichia coli accumulated a substance related to 5-amino-iV-D-ribosyl-4-imidazolecarboxamide. Its ultraviolet absorption spectrum and its diazo chromogen spectrum differed from those of the known D-ribosyl derivative. Escherichia coli (strain B-96) converts it to 5-amino-4-imidazolecarboxamide, and it can be utilized by Escherichia coli B. It was suggested that it is an amino-(D-ribosyl)-imidazole. The accumulation of this substance was, however, somewhat surprising, since bacterial extracts of the purine-requiring mutant effected synthesis of 5-amino-4-imidazolecarboxamide from o-ribose 5-phosphate together with adenosine 5-triphosphoric acid and an energy source. 

Mean-field theory can be used to predict the effects of mutation rate, landscape ruggedness, and parental fitness on the moments of the mutant fitness distribution1791. In this analysis, only the portion of the mutant distribution that is not dead (zero fitness) or parent (unmutated) is considered. The mutant effects are averaged over the transition probabilities. In order to obtain the fitness distribution, two sets of probabilities are required (1) the probabilities P (o) that a particular amino acid identity o exists at a residue i, and (2) the transition probabilities that one amino acid... 

OmpF and Mutants Effects of Dielectric Constant and Interactions Between Residnes. 

Wertz, G. W., and Levine, M., 1973, RNA synthesis by vesicular stomatitis virus and a small plaque mutant Effects of cycloheximide, J. Virol, 12 253. 

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