SOMATIC CROSSING OVER IN GLYCZNE M A X ( L . ) MERRILL : MUTAGENICITY OF SODIUM AZIDE AND LACK OF SYNERGISTIC EFFECT WITH CAFFEINE AND MITOMYCIN C *
Glycine max (soybean) is one angiosperm which lends itself to the study of somatic crossing aver. This is made possible because some varieties have gene combinatiorrs Y l l Y l l , Y, ,y l1 and y l l y l l in the segregating populations from Y,,y , , plants. The gene in question is responsible for chlorophyll synthesis. The Y I I Y , , plants have dark green leaves, Y l l y l l are light green and yl1ylI plants are golden yellow. The heterozygous plants have dark green, yellow and dark green-yellow (double) spots on the leaves of the untreated control material, whereas the two homozygotes are almost always devoid of somatic sectoring. Application of caffeine, or mitomycin C, to the seeds increased the frequency of double, dark green and yellow spots on the Y,,y , , background. Possibly, some dark green or yellow spots originate by failure of one of the two components of what might start as a double spot due to somatic crossing over. The application of NaN, increases the frequency of dark green or yellow spots, almost exclusively. The two spots increase in equal frequency. The y J l y l l plants so treated do not have any light green sectors, but dark green, Y,,Y,,, plants do develop a few light green or very dark green spots. The data indicate that NaN, is capable of inducing nondisjunction, but does not cause mutations (at this locus), chromosome fragmentations (segmental losses) or somatic crossing over to an appreciable degree. It has previously been shown that caffeine-induced chromosome rejoining in Vi& faba can be inhibited by treating the roots with NaN,. In the present experiments NaN, did not affect the processes of somatic crossing over as induced by caffeine or mitomycin C. The effect was additive. This system offers advantages for studying chemical mutagins in that somatic crossing over, point mutations, segmental losses through chromosome breakage and nondisjunction can all be studied in a single treatment to the seeds. ODIUM azide (NaN3) is an inhibitor of oxidative phosphorylation (LOOMIS and LIPMANN 1949). It has been shown to reduce ATP level in excised root tips of Vi& faba at concentrations around 10-4M, within one half hour (KIHLMAN et al. 1971b). This reduction in the level of ATP has been suggested to be responsible for a reduction in the frequency of 8-ethoxycaff eine-induced chromosome exchanges when NaN, is administered just before, or simultaneously with, Publication No. 504, from the Department of Biology, University of Nevada at Reno. The author is thankful for the help received from the Research Advisory Board of the University and for the renew of the manuscript by DR. R. A. NILAN. Genetics 7 5 : 265-277 Octoher. 1973.
EFFECT OF SODIUM AZIDE ON RADIATION DAMAGE AND PHOTOREACTIVATION
During investigations on the role of bacterial pigments in ultraviolet irradiation damage and in photoreactivation, several agents were tested as suppressors of pigmentation effects. Chromobacterium violaceum is extremely radiosensitive in that it shows very high inactivation by ultraviolet and also high photorecovery with white light. Sodium azide depresses both of these effects significantly. Previously, Wyss et al. (1948) demonstrated an increase in the mutation rate of Micrococcus pyogenes var. aureuw, grown in the presence of subinhibitory concentrations of this compound, and Clark et al. (1950) were able to stimulate recombination in Escherichia coli, strain K-12, under the same conditions. On the other hand, Bacq and Herve (1951) report a protective effect of azide and other respiratory poisons against X-ray damage in mice. A correlation of these effects with the known inhibitory action of azide on various iron-porphyrin enzymes appears evident, and an investigation of its applicability to other systems seemed to warrant testing on a broader basis.
Serum Profiles of Luteinizing Hormone, Oestradiol and Cholesterol and Ovarian Functions in Layer Poultry Birds (Gallus domesticus) Fed Diets Containing Furazolidone
This study was carried out to assess the serum profiles of luteinizing hormone (LH), oestradiol, cholesterol and ovarian functions in layer poultry birds (Rhode Island Red;Gallus domesticus) fed a diet containing various concentrations of furazolidone (FZ). A total of 40 birds were randomly assigned to receive FZ 0, 200, 400 or 800 mg/kg feed (ppm) daily during the pre-laying age, i.e. 13–18 weeks (for 5 weeks). Blood samples were collected at weekly intervals. Concentrations of LH and oestradiol in serum were estimated at alternate weeks using radioimmunoassays. Serum cholesterol levels were analysed by an enzymatic calorimetric method. Furazolidone administration was terminated at the 18th week of age. The birds were sacrificed at 22nd week of age and ovarian tissues were processed for morphometric studies. Serum LH, oestradiol and cholesterol levels were affected by age (p<0.001) and FZ dose (p<0.001). Serum LH and oestradiol levels were lower (p<0.05) in birds receiving FZ 800 mg/kg feed daily compared with the controls, whereas serum cholesterol profiles were lower (p<0.05) in all FZ-administered groups than in the control group. The mean weight of ovaries having no yolky follicles observed in the group receiving FZ 400 or 800 mg/kg feed per day was reduced (p<0.05) compared with the control group. Dosing FZ at 800 mg/kg feed per day reduced (p<0.05) the mean volume of ovaries having no yolky follicles compared with the control group. In birds receiving FZ 800 mg/kg feed per day, the mean length of the oviduct was reduced (p<0.05) as compared with the control group. Morphometric studies revealed that the mean number of oocytes with diameter in the range 401–800 μm decreased (p<0.05) in birds fed FZ 400 or 800 mg/kg feed per day. Initial egg production was affected by age (p<0.001) and dose (p<0.001) of FZ. The mean number of eggs laid by different groups revealed that egg production was reduced (p<0.05) in birds receiving FZ 800 mg/kg feed per day as compared with the controls. The present data suggest that FZ causes suppression in serum profiles of LH, oestradiol, cholesterol and ovarian functions in Rhode Island Red layer poultry birds. Therefore, great care must be taken with use of FZ in layer poultry birds (Gallus domesticus) with regard to dosage and duration of administration.