The Effects of Isoflavones on Androgens and Glucocorticoids During Puberty on Male Wistar Rats

Isoflavones are the most common phytoestrogens found in human diets. However, it is still not clear whether isoflavones have effects on the reproductive and the endocrine systems under normal dietary intake and overdose. The aim of this study was to determine how the most important isoflavones, genistein and daidzein, affect androgen and glucorticoid levels on male prepuberal rats. A hundred and seventy‐five 30‐day‐old male Wistar rats were dosed orally by stomach tube every day for 35 days, with saline solution, low and high doses of genistein, daidzein and a mixture of both. Serum samples were analysed by an enzyme immunoassay for hormone determinations. In control group, there was a peak of testosterone (T) and dihydrotestosterone levels associated to the onset of puberty, at the third week. However, in low‐dose groups, the same peak was found at the fourth week (p < 0.05), indicating a delay in the onset of puberty in these groups. Moreover, high doses groups serum androgen levels were significantly lower (p < 0.05) than the control group from the first week until fifth week. This fact was supported by a epididymal histological analysis that indicate in low doses there were several content of spermatozoa at fourth week and in high doses there were few content of spermatozoa. Besides, corticosterone levels followed the same pattern of androgens in all groups. We can conclude that oral administration of isoflavones in male rats decreased the secretion of androgens and glucocorticoids causing a delay in the onset of puberty and may cause physiological and developmental problems.     

Detection and Characterization of the Cumulene Carbenes H2C5 and H2C6

Two cumulene carbenes, H2C5 and H2C6, were detected in a supersonic molecular beam by Fourier transform microwave spectroscopy. Their rotational and leading centrifugal distortion constants were determined with high accuracy, such that the entire radio spectrum can now be calculated. Like the known carbenes H2C3 and H2C4, both molecules have singlet electronic ground states and linear carbon-chain backbones. They can be produced in sufficiently high concentrations in the laboratory that their electronic spectra, expected to lie in the visible, should be readily detectable by laser spectroscopy. The microwave spectra of other, more exotic isomers may be detectable as well.     

Methane uptake in soils from Pinus radiata plantations, a reverting shrubland and adjacent pastures: Effects of land-use change, and soil texture, water and mineral nitrogen

Afforestation and reforestation of pastures are key land-use changes in New Zealand that help sequester carbon (C) to offset its carbon dioxide (CO₂) emissions under the Kyoto Protocol. However, relatively little attention has been given so far to associated changes in trace gas fluxes. Here, we measure methane (CH₄) fluxes and CO₂ production, as well as microbial C, nitrogen (N) and mineral-N, in intact, gradually dried (ca. 2 months at 20 °C) cores of a volcanic soil and a heavier textured, non-volcanic soil collected within plantations of Pinus radiata D. Don (pine) and adjacent permanent pastures. CH₄ fluxes and CO₂ production were also measured in cores of another volcanic soil under reverting shrubland (mainly Kunzea var. ericoides (A. Rich) J. Thompson) and an adjacent pasture. CH₄ uptake in the pine and shrubland cores of the volcanic soils at field capacity averaged about 35 and 14 μg CH₄-C m⁻² h⁻¹, respectively, and was significantly higher than in the pasture cores (about 21 and 6 μg CH₄-C m⁻² h⁻¹, respectively). In the non-volcanic soil, however, CH₄-C uptake was similar in most cores of the pine and pasture soils, averaging about 7-9 μg m⁻² h⁻¹, except in very wet samples. In contrast, rates of CO₂ production and microbial C and N concentrations were significantly lower under pine than under pasture. In the air-dry cores, microbial C and N had declined in the volcanic soil, but not in the non-volcanic soil; ammonium-N, and especially nitrate-N, had increased significantly in all samples. CH₄ uptake was, with few exceptions, not significantly influenced by initial concentrations of ammonium-N or nitrate-N, nor by their changes on air-drying. A combination of phospholipid fatty acid (PLFA) and stable isotope probing (SIP) analyses of only the pine and pasture soils showed that different methanotrophic communities were probably active in soils under the different vegetations. The C18 PLFAs (type II methanotrophs) predominated under pine and C16 PLFAs (type I methanotrophs) predominated under pasture. Overall, vegetation, soil texture, and water-filled pore space influenced CH₄-C uptake more than did soil mineral-N concentrations.     

An Analysis of Seed Development in Pisum sativum. XIII. The Chemical Induction of Storage Product Mutants

In an attempt to generate more variation of the type represented by the rugosus loci, r and rb, putative seed development mutants have been isolated from peas (Pisum sativum L.) following chemical mutagenesis of a round-seeded (RRRbRb) genotype. The populations segregating for wrinkled seeds at the M3 generation were examined for their starch, lipid and protein content. The starch content of the wrinkled-type variants was between 0 and 55 % with an amylose content between 0 and 80 %, compared with 51 % and 30 %, respectively, for the round-seeded parent. When the range of compositions of the wrinkled-type seed was grouped, the values indicated that similar phenotypic groups to the wild type (RRRbRb) and the rugosus types (rrRbRb, RRrbrb and rrrbrb) existed in the population. The lipid content of the putative mutants supported this conclusion. Furthermore, some of the values for starch content and composition, and for lipid content indicated that new mutants had been induced. The material represents the first report on chemically-induced mutants of legumes with altered storage product composition.     

An Analysis of Seed Development in Pisum sativum L. IX. Genetic Analysis of Lipid Content

The objective was to study the genetic basis of lipid content in pea seeds and the extent to which the inheritance of lipid content can be attributed to major genes determining seed shape. The genetic analysis consisted of two full 5 × 5 diallel crosses; one diallel between genotypes differing for genes affecting seed shape (r, rb, di and mifo loci) and the other between genotypes known to differ for lipid content. The results indicated that there was significant additive genetic and dominance variation for percent lipid. Recessive alleles at the r and rb loci have a positive effect on lipid content, while alleles at the di and mifo loci appear to have no effect on lipid content.     

An analysis of seed development in Pisum sativumL. XVI. Assessing variation for fatty-acid content by use of a non-destructive technique for single-seed analysis

Analyses of seeds from a wide range of pea lines have revealed extensive variation for all of the major fatty acids normally found in pisum. Unlike total lipid content, this variation was not affected by the presence of mutant alleles at the r and rb loci. To allow chemically analysed seed to be used in crosses, which is of particular importance for F₂ seed, a method has been developed by which individual seeds can be analysed non-destructively. This system entails drilling a small hole in the seed, away from the embryonic axis. The small quantity of powder produced by this process can be used for the chemical analysis but does not prevent the seed from being grown to produce progeny. Reducing the sample size had no significant effect upon the compositional analysis of the fatty acids.     

The effects of nitrogen level on the performance of Antirrhinum cultivars grown in greenhouse conditions

Summary The effects of nitrogen level on characters relating to the performance of four early and three late flowering cultivars of Antirrhinum majus were assessed. Biometrical techniques were used to distinguish the effects of nitrogen from those due to sowing time and to varietal differences. The usefulness of these techniques to the breeder and to the grower are outlined.     

Comparative studies within and between seed and seedling populations of leafed, ‘leafless’ and ‘semi-leafles’ genotypes of Pisum sativum L.

In an attempt to explain previously observed differences between the growth rates of leafless and conventional plants, we have compared representatives of three pea phenotypes; conventional (AfAfStSt), semileafless (afafStSt) and leafless (afafstst) with regard to their embryonic axis/embryo weight ratio and their patterns of pre-emergent growth. Within each phenotype, comparisons were made between genotypes which differed for mean weight per seed and between seed weight classes within each genotype. Although significant differences were found between genotypes for embryonic axis/embryo weight ratios, these could not be attributed to differences between phenotypes. Within each seed population there was a consistent decrease in this weight ratio with increasing seed size irrespective of phenotype.Relative growth rate (RGR) of the seedlings prior to emergence was similar for all genotypes within and between phenotypes and also for seed size classes from individual populations. There was however a positive relationship betweed seed size and absolute growth rate within and between seed populations.The results suggest that differences between the phenotypes do not become manifest until after emergence of the seedling from the soil and the possibility of a post-emergent lag phase in the leafless type is therefore suggested.     

The induction by mutation of all-year-round flowering in Streptocarpus

Summary A mutant form of Streptocarpus cv. Constant Nymph has been induced by X-irradiation, which shows a drastic change in its flowering habit. whereas the original form flowers under long-day conditions the mutant flowers under both long- and short-day conditions. The relative performance of these two genotypes in defined growth-room conditions and under natural short-days in the glasshouse is described, as well as the response of the plants to certain growth hormones.