Use of a New Buffer System with Formalinized Sheep Erythrocytes in the Rubella Hemagglutination-Inhibition Test

The increased sensitivity and improved agglutination and settling patterns of formalinized sheep erythrocytes in a new buffer, HEPES (N-2-hydroxyethylpiperazine N'-2'-ethanesulfonic acid), make this system more suitable for use in the rubella hemagglutination-inhibition test.     

Influence of added limestone and fertilizers upon the micro-nutrient content of forage tissue and soil

Summary Five rates of limestone and 4 rates of fertilizers were used in a split-plot design to study their effects under field conditions on Mo, Cu, B, Mn, and Zn levels in mixed forage tissue and soil, and on the forage yield. An increase in soil pH resulted in an increase in Mo and Cu content of plant tissue while B, Mn, and Zn decreased. The micro-nutrient content of the tissue increased as the harvesting season progressed. Increasing rates of applied fertilizer did not affect the micro-nutrient content of the forage tissue or soil. Liming to a pH of 5.6 and above reduced the availability of Mn and Zn in the soil. In general, the available B was low at pH values greater than 6.1. Lime did not affect the quantities of Mo and Cu in the soil. Manganese is supplied in large quantities by limestone and is not apt to be deficient in limed soil. However, addition of B and Zn may be required on the high pH soils of Eastern Canada in future. Molybdenum was adequate where the soil was limed to a pH of 6.1 or greater. The dry-matter yield of forage increased significantly with successive increases in lime up to pH 6.6 and with each increment of fertilization. Contribution No.226, Research Branch, Research Station, P.O. Box 1210, Charlottetown, P.E.I. and No.166, Experimental Farm, Nappan, N.S.     

Effect of N,P, and K on root yield and nutrient levels in the leaves and roots of rutabagas grown in a greenhouse

Summary Experiments were conducted to determine the influence of N, P, and K and of the NP and NK interactions on root yields and tissue concentrations of N, P, and K of rutabagas grown on a sandy loam soil under greenhouse conditions. Root yields were increased by applications of N and K but not by added P. The yield response to N was dependent on K supply. The highest dry matter content in roots was associated with the lowest rates of N and K and the lowest root yields. The N content of tissue at the early vegetative stage increased with increasing rates of N and decreased with increasing rates of P and K. The N content of root tissue at harvest increased at the highest rates of N but was unaffected by rates of P and K. The P and K content of root tissue increased with increasing rates of P and K, respectively. The levels of nutrients in early vegetative tissue associated with optimum yields were about 2.6, 0.24, and 2.0% for N, P, and K, respectively. The corresponding values in the leaf tissue at harvest were about 1.2, 0.12, and 1.5% N, P, and K, respectively. Contribution No.222.     

Lack of Chemically Induced Mutation in Repair-Deficient Mutants of Yeast

Two genes, rad6 and rad9, that confer radiation sensitivity in the yeast Saccharomyces cerevisiae also greatly reduce the frequency of chemically-induced reversions of a tester mutant cyc1-131, which is a chain initiation mutant in the structural gene determining iso-1-cytochrome c. Mutations induced by ethyl methanesulfonate (EMS), diethyl sulfate (DES), methyl methanesulfonate (MMS), dimethyl sulfate (DMS), nitroquinoline oxide (NQO), nitrosoguanidine (NTG), nitrogen mustard (HN2), beta-propiolactone, and tritiated uridine, as well as mutations induced by ultraviolet light (UV) and ionizing radiation were greatly diminished in strains homozygous for either the rad6 or rad9 gene. Nitrous acid and nitrosoimidazolidone (NIL), on the other hand, were highly mutagenic in these repair-deficient mutants, and at low doses, these mutagens acted with about the same efficiency as in the normal RAD strain. At high doses of either nitrous acid or NIL, however, reversion frequencies were significantly reduced in the two rad mutants compared to normal strains. Although both rad mutants are immutable to about the same extent, the rad9 strains tend to be less sensitive to the lethal effect of chemical mutagens than rad6 strains. It is concluded that yeast requires a functional repair system for mutation induction by chemical agents.     

Gene Differences between the Sex Ratio and Standard Gene Arrangements of the X Chromosome and Linkage Disequilibrium between Loci in the Standard Gene Arrangement of the X Chromosome in DROSOPHILA PSEUDOOBSCURA

The Standard and Sex Ratio gene arrangements of the X chromosome of D. pseudobscura differ from each other in allele frequencies at the four X chromosome loci, esterase-5, adult acid phosphatase-6, phosphoglucomutase-1 and octanol dehydrogenase-3. The Standard arrangement which is the common arrangement in all populations is polymorphic at these loci in varying degrees, the geographically less widespread Sex Ratio arrangement has little polymorphism and is genically predominantly E-5(1.04) AP-6(-) Pgm1(1.0) ODH-3(1.0). The Sex Ratio arrangement from different populations is alike at all of the four loci, the Standard arrangement shows some gene frequency differences among populations. The Standard and Sex Ratio arrangements differ from each other by three inversions which suggests that the two arrangements are "old". Gene differences between these two chromosome arrangements can be explained due to differential natural selection of alleles in the Standard and Sex Ratio arrangments.-The order and percent recombination among these four loci in the Standard arrangement are: E-5-.294-AP-6-.335-Pgm-1-.024-ODH-3. The Standard X chromosomes from four different wild populations were analyzed for evidence of linkage disequilibrium between pairs of loci at these four loci. No evidence of linkage disequilibrium between pairs of loci was obtained. However, when linkages involving simultaneously three loci, E-5, AP-6 and Pgm-1 are considered, then significant departure from linkage equilibrium is observed.     

Association of Alleles of the Malic Dehydrogenase Locus with a Pericentric Inversion in DROSOPHILA ROBUSTA

Associations of Malic dehydrogenase alleles with the third chromosome arrangement 3R and the pericentric arrangement 3L-R are described. Even though significant associations between alleles and inversions exist within a population, there is an overall similarity in MDH allele frequencies in different populations inspite of large differences in inversion frequencies.     

Inter-character relationships and heterosis observed in opaque-2 maize crosses and in their normal analogues

Summary Hybrids obtained from two series of diallel crosses made between six o ₂ converted inbred lines on the one hand and their normal analogues on the other were compared for twenty-five characters including yield and several of the yield components, including the parents. Observations on simple inter-character correlation coefficients presented here have shown that the majority of the correlations at the o ₂ level are of the same order as at the normal level. A number of correlations of the o ₂ type are inferior to those of their normal analogues, whereas a few are favoured by the o ₂ gene including the correlation of grain yield with kernels per row. A measure of heterosis for each hybrid over its mid-parent also demonstrated that the o ₂ types show poorer heterosis in more cases than do their normal counterparts. Still, in nearly 40 percent of the cases the o ₂ hybrids were found to be more heterotic than their normal analogues, particularly for the various maturity characters and several of the yield components. Thus, the possibility of improvement exists in breeding maize with the opaque-2 gene.