scholarly journals SOMATIC MUTATIONAL TRANSIENTS. III. RESPONSE BY TWO GENES IN A CLONE OF NICOTIANA TO 24 ROENTGENS OF GAMMA RADIATION APPLIED AT VARIOUS INTENSITIES

Genetics ◽  
1973 ◽  
Vol 75 (1) ◽  
pp. 93-111
Author(s):  
Seaward A Sand ◽  
Harold H Smith
Keyword(s):  
Linear Functions ◽  
Mutation Rates ◽  
Response Curves ◽  
Constant Intensity ◽  
Dose Rate Effects ◽  
Rate Effects ◽  
Average Control ◽  
V Gene ◽  
Effects Of Radiation ◽  
And Control

ABSTRACT Somatic effects of radiation intensity on the mutable V and stable R genes were detected in plants of a heterozygous clone (vS3/vs, R/r) subjected to the same dose at four rates. The effects were compared by counting speckled and purple sectors in flowers from irradiated and control plants. Response curves were estimated from the mutant sector averages, observed over a period of transient response for successive mature flowers. A structure for integrating the mutational contributions from different flowers was provided by models. The average control mutation rates are 8,110 per 107 cells for the V gene, and 49.45 for R. At a constant intensity of 4320 roentgens/hour, average induced mutation rates per 107 cells per roentgen for V increase from 194 (at 24 r total dose) to 1,116 (at 3 r dose); the corresponding rates for R increase from 7.24 to 27.65. With these responses as standards, both genes at corresponding total doses yield lower rates at lower intensities. For the series of intensities 1.2, 0.6, 0.3 and 0.15 roentgens/hour, the decreases in mutation rate for the V gene are, respectively, 66, 148, 315, and 617 per 107 cells per roentgen. The corresponding decrements for R are 4.86, 8.70, 14.61, and 23.51. These effects are non-linear functions of intensity for both genes, but V is at least 13 times as sensitive as R. Radiation operating to extinguish a buffering system against final mutation can account for the dose and dose-rate effects observed.

EVOLUTION WITH ENDOGENOUS MUTATIONS

2005 ◽  
Vol 07 (02) ◽  
pp. 229-240 ◽  
Author(s):  
IVAR KOLSTAD
Keyword(s):  
Evolutionary Dynamics ◽  
Basin Of Attraction ◽  
Equilibrium Selection ◽  
Mutation Rates ◽  
And Control

Bergin and Lipman (1996) prove that equilibrium selection in the evolutionary dynamics of Kandori et al. (1993) and Young (1993), is not robust to variations in mutation rates across states. Specifically, a risk dominant equilibrium can be selected against if mutation rates are higher in its basin of attraction than elsewhere. Van Damme and Weibull (1998) model mutations as a compromise between payoff losses and control costs, which implies lower mutation rates in the risk dominant equilibrium. This paper argues that this result is not driven by control costs, but by players focusing on payoff losses when choosing mutation rates.

scholarly journals Bioindicator demonstrates high persistence of sulfentrazone in dry soil1

2015 ◽  
Vol 45 (3) ◽  
pp. 326-332 ◽  
Author(s):  
Renato Coradello Lourenço ◽  
Saul Jorge Pinto de Carvalho
Keyword(s):  
Dose Response ◽  
Residual Effect ◽  
Second Phase ◽  
Response Curves ◽  
Sugarcane Crop ◽  
Phytotoxic Activity ◽  
Dry Soil ◽  
Two Phases ◽  
Preemergence Herbicides ◽  
And Control

ABSTRACTIn sugarcane crop areas, the application of preemergence herbicides with long residual effect in the soil has been frequently necessary. The herbicide persistence in the soil must be high especially because of applications during the dry season of the year, after sugarcane harvest. This study aimed at estimating the sulfentrazone persistence and dissipation in dry soil using bioindicator. Five experiments were carried out, divided into two phases. In the first phase, three dose-response curves were adjusted to select the best bioindicator to be adopted in the second phase. Niger was adopted due to its lower sensibility to sulfentrazone. In the second phase, a new dose-response curve was carried out, with six doses of sulfentrazone, in order to standardize the bioindicator sensibility to sulfentrazone. At the end, another experiment with six periods of sulfentrazone persistence in dry clay soil was developed. Persistence periods were: 182, 154, 125, 98 and 30 days. The bioindicator was seeded at the application day in treated plots and control. In this experiment, the sulfentrazone dose applied was 800 g ha-1. Niger was considered a good species to estimate the sulfentrazone persistence in dry soil. The sulfentrazone phytotoxic activity was identified up to 182 days after application, and its average dissipation rate was 2.15 g ha-1 day-1, with half-life higher than 182 days.

scholarly journals Investigation of dose-rate effects and cell-cycle distribution under protracted exposure to ionizing radiation for various dose-rates

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Yusuke Matsuya ◽  
Stephen J. McMahon ◽  
Kaori Tsutsumi ◽  
Kohei Sasaki ◽  
Go Okuyama ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Ionizing Radiation ◽  
Dose Rate ◽  
Cell Cycle Distribution ◽  
Dose Rates ◽  
Dose Rate Effects ◽  
Rate Effects

In vitro photodynamic therapy of human lung cancer: Investigation of dose-rate effects

Lung Cancer ◽  
1990 ◽  
Vol 6 (1-2) ◽  
pp. 63
Author(s):  
W Matthews ◽  
J Cook ◽  
JB Mitchell ◽  
RR Perry ◽  
S Evans ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Photodynamic Therapy ◽  
Dose Rate ◽  
Human Lung ◽  
Human Lung Cancer ◽  
Dose Rate Effects ◽  
Rate Effects

Development of Decreased Insulin-Induced Glucose Transport in Skeletal Muscle of Glucose-Intolerant Hybrids of Diabetic GK Rats

1995 ◽  
Vol 88 (3) ◽  
pp. 301-306 ◽  
Author(s):  
Lorraine A. Nolte ◽  
Samy M. Abdel-Halim ◽  
Iva K. Martin ◽  
Amel Guenifi ◽  
Juleen R. Zierath ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Blood Glucose ◽  
Glucose Transport ◽  
Glucose Intolerance ◽  
Dose Response ◽  
Insulin Dose ◽  
Age Groups ◽  
Plasma Free Fatty Acid ◽  
Response Curves ◽  
And Control

1. The effect of glucose intolerance on insulin-stimulated glucose transport in isolated skeletal muscles was investigated in male F, hybrids of spontaneously diabetic GK (Goto—Kakizaki) and control Wistar rats at 1 and 2 months of age. 2. Hybrid rats are characterized by markedly impaired glucose-induced insulin secretion. The area under the blood glucose curve was significantly higher following an intraperitoneal glucose injection (2 g/kg) in hybrid rats in both age groups than in the control rats (P < 0.001). In 2-month-old hybrid rats the incremental area under the insulin curve during the intraperitoneal glucose tolerance test was not different from that of control rats. Serum cholesterol, triacylglycerol or plasma free fatty acid levels did not differ between the groups. Fasting and post-prandial plasma glucose concentrations were elevated in 2-month-old hybrid rats compared with control rats (54%, P < 0.05, and 27%, P < 0.05, respectively), but were not differerent in 1-month-old rats. Plasma insulin did not differ between the hybrid and control rats in the fasting or post-prandial state at either age studied. 3. The insulin dose—response curves for 3-O-methylglucose transport did not differ between 1-month-old hybrid and control rats for either the soleus or epitrochlearis muscle. The insulin dose—response curve for the epitrochlearis, but not for the soleus, muscle from 2-month-old hybrid rats was shifted to the right compared with the curve from the control animals (P < 0.05). 4. In conclusion, the hybrid rat is a non-obese, non-hyperinsulinaemic animal model, which at a young age is characterized by impaired insulin secretion and moderate glucose intolerance. In this glucose-intolerant rat model, mild peripheral insulin resistance gradually develops, as reflected by the decreased insulin-induced glucose transport in the fast-twitch epitrochlearis muscle. It is suggested that the elevated blood glucose per se may have contributed to the slight decrease in peripheral insulin action.

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