Effects of Radiation and Chemical Mutagenesis on Expression of Aflatoxigenic Traits in Aspergillus parasiticus SMS08-C

Abstract In 1928, the Swedish geneticists Herman Nilsson-Ehle and Åke Gustafsson started to act on their own ideas with the first experiments with induced mutations using diploid barley. They started with X-rays and UV irradiation. Very soon the first chlorophyll mutations were obtained and followed by the first 'vital' mutations Erectoides (ert) (Franckowiak and Lundqvist, 2001). Several other valuable mutations were identified as early maturity, high yielding, lodging resistant and characters with altered plant architecture. The experiments expanded to include other different types of irradiation, followed by chemical mutagenesis starting with mustard gas and concluding with sodium azide. The research brought a wealth of observations of general biological importance, such as the physiological effects of radiation as well as the difference in the mutation spectrum with respect to mutagens. This research was non-commercial, even if some mutants have become of important agronomic value. It peaked in activity during the 1950s to 1980s and, throughout, barley was the main experimental crop. About 12,000 different morphological and physiological mutants with a very broad phenotypic diversity were brought together and are incorporated in the Nordic Genetic Resource Centre (NordGen), Sweden. Several important mutant groups have been analysed in more detail genetically, with regard to mutagen specificity and gene cloning. These are: (i) early maturity mutants (Praematurum); (ii) six-rowed and intermedium-spike mutants; (iii) mutants affecting surface wax coating (Eceriferum); and (iv) mutants affecting rachis spike density (Erectoides). Some of these groups are presented in more detail in this review. Once work with induction of mutations began, it was evident that mutations should regularly be included in breeding programmes of crop plants. In Sweden, direct X-ray induced macro-mutants have been successfully released as cultivars, some of them having been used in combination breeding. Their importance for breeding is discussed in more detail.

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Male-mediated developmental defects and childhood disease

Reproductive Medicine Review ◽

10.1017/s0962279900000211 ◽

2000 ◽

Vol 8 (2) ◽

pp. 107-126 ◽

Cited By ~ 10

Author(s):

DE Sawyer ◽

RJ Aitken

Keyword(s):

Middle Ages ◽

Chromosomal Abnormalities ◽

Chemical Mutagenesis ◽

Laboratory Animals ◽

X Rays ◽

Developmental Defects ◽

Developmental Problems ◽

Mediated Effects ◽

Male Germline ◽

Effects Of Radiation

Reproductive and developmental toxicology has existed, in some form, at least since the Middle Ages when women commonly used naturally derived abortifacients for birth control. Percival Pott was the first to observe that environmental exposures could detrimentally affect the male reproductive system. He noticed that chimney sweeps exposed to soot developed testicular cancer and infertility at unusually young ages. The formal investigation of male-mediated effects on offspring (germline mutagenesis) began with the pioneering studies of Muller, Hertwig, Snell, Brenneke, and others, who established X-rays as the first identified agent capable of inducing hereditary changes in mice. They showed that litters sired by irradiated males contained fewer pups than controls. Because sperm motility and density were not affected, but chromosome abnormalities were found in fertilized eggs, they concluded that irradiated sperm were the source of the abnormal chromosomes. Since that discovery, the mutagenic effects of radiation on the male germline have been studied extensively (see below). Later, Auerbach & Robson and Bock & Jackson were the first to demonstrate that exposing mice to chemicals decreases their fertility and induces chromosomal abnormalities and other mutations in the male germline. The subsequent five decades of work on chemical mutagens has resulted in a detailed biochemical and genetic characterization of chemical mutagenesis in the male germline and male-mediated developmental problems in laboratory animals (see below).

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INDUCED GENETIC VARIABILITY IN SESAME (Sesamum indicum L): A COMPARATIVE STUDY ON THE MUTAGENIC EFFECTS OF RADIATION AND EMS IN SEED GERMINATION, POLLEN VIABILITY AND CHLOROPHYLL MUTANTS

Journal of Experimental Biology and Agricultural Sciences ◽

10.18006/2020.8(6).774.788 ◽

2020 ◽

Vol 8 (6) ◽

pp. 774-788

Author(s):

Parthasarathi G ◽

◽

Sugitha Thankappan ◽

M. Arumugam Pillai ◽

R. Kannan ◽

...

Keyword(s):

Gamma Rays ◽

Pollen Viability ◽

Crop Improvement ◽

Lethal Dose ◽

Probit Analysis ◽

Chemical Mutagenesis ◽

Improvement Program ◽

Dependent Relationship ◽

Chlorophyll Mutants ◽

Effects Of Radiation

The present study envisaged the effects of two mutagens, gamma rays and EMS on the phenotypes of two sesame varieties viz., TMV7 and SVPR1. A known quantity of dry, uniform, and healthy seeds of TMV7 and SVPR 1 were irradiated using Co60 (Cobalt 60) with different doses (250, 300, 350, 400, 450 Gy) of gamma rays. For chemical mutagenesis, different concentrations of EMS @ 0.20%, 0.40% and 0.60% was used and treated for 8 h. The dose-response curve of the probit analysis showed that the optimal lethal dose for SVPR1was lower than TMV7. The expected LD50 values of gamma radiation for TMV 7 and SVPR1 were 403.91Gy and 343.84Gy, respectively. For EMS, the expected LD50 values are 0.525 % and 0.276% for TMV7 and SVPR1 respectively. Germination and pollen fertility declined linearly with an increase in dose or concentration of the mutagens. Three classes of chlorophyll mutants viz., xantha, chlorine, and viridis in M2 generation reveals a dose dependent relationship between mutagens and frequency of chlorophyll mutants. Mutagenic effectiveness was higher at lower doses whereas mutagenic efficiency was observed higher at extremity doses in both the varieties. The overall considerations on M1 generation effects showed that SVPR1was highly sensitive to gamma rays and TMV7 produced more viable mutationsthan SVPR1. The current studies suggest gamma rays as an efficient mutagen to induce essential mutations in TMV7 for the further crop improvement program.

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Elastic Scattering in Electron Microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100071703 ◽

1973 ◽

Vol 31 ◽

pp. 252-253

Author(s):

J. Langmore ◽

M. Isaacson ◽

J. Wall ◽

A. V. Crewe

Keyword(s):

Electron Microscopy ◽

Elastic Scattering ◽

Cross Section ◽

Quantum Noise ◽

Dark Field ◽

Elastic Cross Section ◽

Biological Molecules ◽

Dark Field Microscopy ◽

Field Systems ◽

Effects Of Radiation

High resolution dark field microscopy is becoming an important tool for the investigation of unstained and specifically stained biological molecules. Of primary consideration to the microscopist is the interpretation of image Intensities and the effects of radiation damage to the specimen. Ignoring inelastic scattering, the image intensity is directly related to the collected elastic scattering cross section, σɳ, which is the product of the total elastic cross section, σ and the eficiency of the microscope system at imaging these electrons, η. The number of potentially bond damaging events resulting from the beam exposure required to reduce the effect of quantum noise in the image to a given level is proportional to 1/η. We wish to compare η in three dark field systems.

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Electron crystallographic determination of the 3-D structure of staurolite at atomic resolution

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010008701x ◽

1991 ◽

Vol 49 ◽

pp. 540-541

Author(s):

Kenneth H. Downing ◽

Hu Meisheng ◽

Hans-Rudolf Went ◽

Michael A. O'Keefe

Keyword(s):

High Resolution ◽

Three Dimensional ◽

High Resolution Electron Microscopy ◽

Atomic Resolution ◽

Dimensional Structure ◽

Structure Information ◽

Resolution Electron ◽

Scattering Effects ◽

High Resolution Images ◽

Effects Of Radiation

With current advances in electron microscope design, high resolution electron microscopy has become routine, and point resolutions of better than 2Å have been obtained in images of many inorganic crystals. Although this resolution is sufficient to resolve interatomic spacings, interpretation generally requires comparison of experimental images with calculations. Since the images are two-dimensional representations of projections of the full three-dimensional structure, information is invariably lost in the overlapping images of atoms at various heights. The technique of electron crystallography, in which information from several views of a crystal is combined, has been developed to obtain three-dimensional information on proteins. The resolution in images of proteins is severely limited by effects of radiation damage. In principle, atomic-resolution, 3D reconstructions should be obtainable from specimens that are resistant to damage. The most serious problem would appear to be in obtaining high-resolution images from areas that are thin enough that dynamical scattering effects can be ignored.

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Electron microscope study of the effects of radiation on insect fertility

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100157905 ◽

1990 ◽

Vol 48 (3) ◽

pp. 72-73

Author(s):

Judy Ju-Hu Chiang ◽

Robert Kuo-Cheng Chen

Keyword(s):

Electron Microscopy ◽

Germ Cell ◽

Germ Cells ◽

Electron Microscope Study ◽

Radiation Treatment ◽

Light And Electron Microscopy ◽

Stem Borer ◽

Metabolic Energy ◽

Rice Stem Borer ◽

Effects Of Radiation

Germ cells from the rice stem borer Chilo suppresalis, were examined by light and electron microscopy. Damages to organelles within the germ cells were observed. The mitochondria, which provide the cell with metabolic energy, were seen to disintegrate within the germ cell. Lysosomes within the germ cell were also seen to disintegrate. The subsequent release of hydrolytic enzymesmay be responsible for the destruction of organelles within the germ cell. Insect spermatozoa were seen to lose the ability to move because of radiation treatment. Damage to the centrioles, one of which is in contact with the tail, may be involved in causing sperm immobility.

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