Effect of temperature, elevated carbon dioxide, and drought during seed development on the isoflavone content of dwarf soybean [Glycine max (L.) Merrill] grown in controlled environments

The effects of elevated temperature, carbon dioxide, and water stress on the isoflavone content of seed from a dwarf soybean line [Glycine max (L.) Merrill] were determined, using controlled environment chambers. Increasing the temperature from 18 degrees C during seed development to 23 degrees C decreased total isoflavone content by about 65%. A further 5 degrees C increase to 28 degrees C decreased the total isoflavone content by about 90%. Combining treatments at elevated temperature with elevated CO(2) (700 ppm) and water stress to determine the possible consequences of global climate change on soybean seed isoflavone content indicated that elevated CO(2) at elevated temperatures could partially reverse the effects of temperature on soybean seed isoflavone content. The addition of drought stress to plants grown at 23 degrees C and elevated CO(2) returned the total isoflavone levels to the control values obtained at 18 degrees C and 400 ppm CO(2). The promotive effects of drought and elevated CO(2) at 23 degrees C on the 6' '-O-malonygenistin and genistin levels were additive. The individual isoflavones often had different responses to the various growth conditions during seed maturation, modifying the proportions of the principal isoflavones. Therefore, subtle changes in certain environmental factors may change the isoflavone content of commercially grown soybean, altering the nutritional values of soy products.     

Vitamin E composition of walnuts (Juglans regia L.): a 3-year comparative study of different cultivars

The tocopherol and tocotrienol composition of walnuts (Juglans regia L.) was determined for nine cultivars (cvs. Arco, Franquette, Hartley, Lara, Marbot, Mayette, Mellanaise, Parisienne, and Rego). Walnuts were harvested over three consecutive years from two different geographical origins (Bragan?a and Coimbra, Portugal), for a total of 26 samples. The methodology employed was a normal-phase high-performance liquid chromatography coupled to a series arrangement of a diode array detector followed by a fluorescence detector, allowing the simultaneous analysis of all tocopherols and tocotrienols. The analyses showed that all samples presented a similar qualitative profile composed of five compounds: alpha-tocopherol, beta-tocopherol, gamma-tocopherol, delta-tocopherol, and gamma-tocotrienol. gamma-Tocopherol was the major compound in all samples, ranging from 172.6 to 262.0 mg/kg, followed by alpha- and delta-tocopherols, ranging from 8.7 to 16.6 mg/kg and from 8.2 to 16.9 mg/kg, respectively. Multivariate analysis of the data obtained showed the existence of significant differences in composition among cultivars. These differences were also significant when cultivars were grouped by year of production, showing that besides genetic factors, the vitamin E composition was influenced by environmental factors.     

Nitrogen-fixing legume tree species for the reclamation of severely degraded lands in Brazil

The main challenges faced in the reclamation of severely degraded lands are in the management of the systems and finding plant species that will grow under the harsh conditions common in degraded soils. This is especially important in extremely adverse situations found in some substrates from mining activities or soils that have lost their upper horizons. Under these conditions, recolonization of the area by native vegetation through natural succession processes may be extremely limited. Once the main physical and chemical factors restrictive to plant growth are corrected or attenuated, the introduction of leguminous trees able to form symbioses with nodulating N?-fixing bacteria and arbuscular mycorrhizal fungi constitutes an efficient strategy to accelerate soil reclamation and initiate natural succession. These symbioses give the legume species a superior capacity to grow quickly in poor substrates and to withstand the harsh conditions presented in degraded soils. In this article we describe several successful results in Brazil using N?-fixing legume tree species for reclamation of areas degraded by soil erosion, construction and mining activities, emphasizing the potential of the technique to recover soil organic matter levels and restore ecosystem biodiversity and other environmental functions.     

Free amino acid composition of quince (Cydonia oblonga Miller) fruit (pulp and peel) and jam

Twenty-one free amino acids present in several samples of quince fruit (pulp and peel) and quince jam (homemade and industrially manufactured) were analyzed by GC/FID. The analyses showed some differences between quince pulps and peels. Generally, the highest content in total free amino acids and in glycine was found in peels. As a general rule, the three major free amino acids detected in pulps were aspartic acid, asparagine, and hydroxyproline. For quince peels, usually, the three most abundant amino acids were glycine, aspartic acid, and asparagine. Similarly, for quince jams the most important free amino acids were aspartic acid, asparagine, and glycine or hydroxyproline. This study suggests that the free amino acid analysis can be useful for the evaluation of quince jam authenticity. It seems that glycine percentage can be used for the detection of quince peel addition while high alanine content can be related to pear addition.     

Genetic selection for enhanced bioavailable levels of iron in bean (Phaseolus vulgaris L.) seeds

The bioavailability of Fe from 24 select genotypes of bean (Phaseolus vulgaris L.) seeds containing a range of concentrations of Fe, myo-inositol pentaphosphate plus phytic acid (IP5+IP6), and tannins was studied using a rat model. Bean accessions, selected from field trials for their variations in Fe, phytate, and tannin seed concentrations, were grown in a greenhouse in nutrient solutions radiolabeled with (59)Fe. Mature seeds were autoclaved and lyophilized. Test meals (containing 1 g of dried bean, 0.5 g of sucrose, and 1 g of basal Fe-deficient diet) were fed to marginally Fe-depleted weanling rats over a 3-h period; rats were radioassayed in a gamma-spectrometer immediately after feeding and daily thereafter for the next 10 d. Radioiron retention data were used to calculate percent Fe absorption (i.e., Fe bioavailability) from the meals. Seed Fe concentrations ranged from 52 to 157 microg g(-)(1) dry weight. There was a tendency to also select for higher Zn concentrations in the beans when selecting for high Fe concentrations. The Fe bioavailability to rats from test meals depended on the genotype and varied from 53% to 76% of the total Fe. Bean genotypes with higher seed Fe concentrations resulted in increased amounts of bioavailable Fe to rats. There was no significant correlation between the Fe concentration in different bean genotypes and Fe bioavailability to rats attributable to variations in IP5+IP6 or tannins, even though these antinutrients varied widely (i.e., from 19.6 to 29.2 micromol of IP5+IP6 g(-)(1) and from 0.35 to 2.65 mg of tannins g(-)(1)) in the test meals. Other unknown seed factors (i.e., antinutrients or promoter substances) may be contributing factors affecting Fe bioavailability from bean seeds.     

Tracks of cosmic rays in plastics

Cosmic ray nuclei have been observed with the use of plastic trackdetecting solids in satellites and high-altitude balloon flights. Nuclear emulsions in the stacks of plastic sheets allowed the positive identification of cosmic raynuclei as light as nitrogen. The most striking new information was the failure to observe relativistic iron nuclei, a result which has led to an advance in the understanding of track registration criteria.     

Conserved structure for single-stranded telomeric DNA recognition

The essential Cdc13 protein in the yeast Saccharomyces cerevisiae is a single-stranded telomeric DNA binding protein required for chromosome end protection and telomere replication. Here we report the solution structure of the Cdc13 DNA binding domain in complex with telomeric DNA. The structure reveals the use of a single OB (oligonucleotide/oligosaccharide binding) fold augmented by an unusually large loop for DNA recognition. This OB fold is structurally similar to OB folds found in the ciliated protozoan telomere end-binding protein, although no sequence similarity is apparent between them. The common usage of an OB fold for telomeric DNA interaction demonstrates conservation of end-protection mechanisms among eukaryotes.     

Selective sensitivity to direction of movement in ganglion cells of the rabbit retina

Among the ganglion cells in the rabbit's retina there is a class that responds to movement of a stimulus in one direction, and does not respond to movement in the opposite direction. The same directional selectivity holds over the whole receptive field of one such cell, but the selected direction differs in different cells. The discharge is almost uninfluenced by the intensity of the stimulus spot, and the response occurs for the same direction of movement when a black spot is substituted for a light spot.