Multiple-Mutation Theory of Carcinogenesis

Nature ◽  
1958 ◽  
Vol 181 (4609) ◽  
pp. 651-652 ◽  
Author(s):  
J. C. FISHER
Keyword(s):  
Multiple Mutation ◽  
Mutation Theory

scholarly journals THE FALLACY OF THE MUTATION THEORY

Science ◽  
1906 ◽  
Vol 23 (593) ◽  
pp. 746-748 ◽  
Author(s):  
A. E. ORTMANN
Keyword(s):  
Mutation Theory

scholarly journals One hundred years of somatic mutation theory of carcinogenesis: Is it time to switch?

BioEssays ◽  
2013 ◽  
Vol 36 (1) ◽  
pp. 118-120 ◽  
Author(s):  
Ana M. Soto ◽  
Carlos Sonnenschein
Keyword(s):  
Somatic Mutation ◽  
Somatic Mutation Theory ◽  
Mutation Theory

scholarly journals The effect of attachment site mutations on strand exchange in bacteriophage lambda site-specific recombination.

Genetics ◽  
1989 ◽  
Vol 122 (4) ◽  
pp. 727-736
Author(s):  
C E Bauer ◽  
J F Gardner ◽  
R I Gumport ◽  
R A Weisberg
Keyword(s):  
Attachment Site ◽  
Strand Exchange ◽  
Segregation Pattern ◽  
Base Substitution ◽  
Base Pairs ◽  
Multiple Mutation ◽  
Attachment Sites ◽  
Dna Strands ◽  
Substitution Mutations ◽  
Overlap Region

Abstract Recombination of phage lambda attachment sites occurs by sequential exchange of the DNA strands at two specific locations. The first exchange produces a Holliday structure, and the second resolves it to recombinant products. Heterology for base substitution mutations in the region between the two strand exchange points (the overlap region) reduces recombination; some mutations inhibit the accumulation of Holliday structures, others inhibit their resolution to recombinant products. To see if heterology also alters the location of the strand exchange points, we determined the segregation pattern of three single and one multiple base pair substitution mutations of the overlap region in crosses with wild type sites. The mutations are known to differ in the severity of their recombination defect and in the stage of strand exchange they affect. The three single mutations behaved similarly: each segregated into both products of recombination, and the two products of a single crossover were frequently nonreciprocal in the overlap region. In contrast, the multiple mutation preferentially segregated into one of the two recombinant products, and the two products of a single crossover appeared to be fully reciprocal. The simplest explanation of the segregation pattern of the single mutations is that strand exchanges occur at the normal locations to produce recombinants with mismatched base pairs that are frequently repaired. The segregation pattern of the multiple mutation is consistent with the view that both strand exchanges usually occur to one side of the mutant site. We suggest that the segregation pattern of a particular mutation is determined by which stage of strand exchange it inhibits and by the severity of the inhibition.

The adaptation of Bact. coli mutabile to lactose

1954 ◽  
Vol 223 (1154) ◽  
pp. 420-420
Keyword(s):  
Inoculum Size ◽  
Colony Development ◽  
Lag Phase ◽  
Normal Cells ◽  
Adaptive Process ◽  
Large Numbers ◽  
Parent Culture ◽  
Mutation Theory ◽  
Special Circumstances ◽  
New Evidence

When Bact. coli mutabile not previously exposed to lactose is plated on lactose-ammonium sulphate agar the number of normal-sized colonies (lac + ) eventually formed is a complicated function of the inoculum size. For small numbers all the cells plated eventually form colonies; for large numbers the colony yield is determined not by a number of mutants in the parent culture but by plate exhaustion (for which the earlier developing colonies are chiefly responsible). The time of appearance of the lac + colonies is much longer than with a culture previously grown in lactose. Thus lac + mutants could not have been present from the start unless their growth is inhibited by an excess of normal cells. When, however, a small number of previously adapted cells are mixed with an excess of unadapted cells the presence of the latter does not impede the development on agar of lac + colonies from the former. When cells are first placed in a liquid lactose medium and samples are transferred at intervals during the ensuing lag phase, the time needed for colony development on lactose-agar progressively diminishes, once again showing that an adaptive process is occurring during the lag in the liquid medium. In certain special circumstances the adaptation to the liquid lactose medium may occur with abnormal speed. The growth rate of newly adapted strains is at first variable. If interpreted by a mutation theory the observations would demand the assumption of a complex polygenetic system for which current applications of the Luria-Delbrück and Lea-Coulson theories would be invalid. Recent arguments about the mutational nature of these phenomena are criticized in the light of the new evidence.

The Diagnostic Method of Concrete Dam Monitoring Information Valid Interval

2012 ◽  
Vol 226-228 ◽  
pp. 2072-2077
Author(s):  
Dong Qin ◽  
Xue Qin Zheng ◽  
Fa Meng Wang ◽  
He Zhi Liu
Keyword(s):  
Influential Factors ◽  
Arch Dam ◽  
Dynamical Structure ◽  
Concrete Dam ◽  
Concrete Arch Dam ◽  
Structural Mutation ◽  
Mutation Theory ◽  
Dam Monitoring ◽  
Mutation Sequence ◽  
Monitoring Information

On the basis of the analysis of the displacement of concrete dam and its related influential factors, based on the evolvement of nonlinear dynamics of concrete dam, it can effectively identify the mutations position of measured value and the attribute interval of dynamical system applied with the wavelet analysis, dynamic structural mutation theory and other numerical analysis methods. When detecting after separating structural mutation sequence, it can finally get the relative stable displacement time series of dynamical structure, so it can realize the diagnostic separation of the monitoring information effective interval. At the end of the paper, through applying a certain concrete arch dam, it is proved that the proposed method of concrete dam mutations diagnosis of is of great significance for the real-time monitoring of the workability state of a dam.

scholarly journals Mitochondrial changes in carcinogenesis as a goal of antitumor therapy (review)

2020 ◽  
pp. 65-73
Author(s):  
T. E. Potemina ◽  
E. V. Guzikov
Keyword(s):  
Malignant Tumors ◽  
Gene Mutations ◽  
Cancer Development ◽  
Antitumor Therapy ◽  
Mutation Theory ◽  
Main Variant

Causes and mechanisms of cancer development are currently one of the urgent problems of medicine. The main variant for today is the mutation theory. Identification of the system of gene mutations, including in mitochondria, leading to this or that type of tumors, made it possible to develop a personalized, so-called targeting, the therapy of malignant tumors.

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