Pre-maturity α-amylase and incipient sprouting in UK winter wheat,with special reference to the variety Rialto

In 1998 and 1999 the UK winter wheat variety Rialto produced unexpected low Hagberg falling numbers that could not be directly linked to sprouting. It was proposed that these reductions in quality could be due to pre-maturity α-amylase activity (PMAA). The problem was not identified during the selection and commercial development stages. Our study tested the hypothesis that the variety Rialto is PMAA-susceptible. Analysis was done on 13 year-location combinations of field grown Rialto. Together, visual and chemical assessments of sprouting and iso-electric focusing of α-amylase isozymes identified several samples with significant α-amylase activity in the apparent absence of sprouting. In addition, tests with α-amylase sensitive Phadebas gel revealed distinctive PMAA discoloration patterns in 10–44% of the grain from the 13 samples, leading to the conclusion that Rialto is PMAA-susceptible. Diurnal temperature range accumulated for an 11 day period during a warm spell in early simulated grain development displayed a significant but negative correlation with the number of grains showing clear PMAA discoloration patterns on Phadebas gel. The number of clear PMAA grains correlated positively with rainfall accumulated over 11 days. These results suggest that PMAA can increase under conditions similar to those conducive to pre-harvest sprouting. It is however also possible that in some instances both PMAA and incipient sprouting could have produced similar patterns of α-amylase activity. In addition to tests with Rialto, Phadebas gel tests were therefore also done with the known high Hagberg varieties Option and Malacca, sprouted in a controlled environment. Results from the additional gel tests suggest that visual and chemical assessments of sprouting in the grain combined with Phadebas gel analysis could identify PMAA more reliably in grain sub-samples than Phadebas gel analysis alone.     

Managing soil fertility in organic farming systems

Abstract. Complex relationships exist between different components of the organic farm and the quantity and quality of the end products depend on the functioning of the whole system. As such, it is very difficult to isolate soil fertility from production and environmental aspects of the system. Crop rotation is the central tool that integrates the maintenance and development of soil fertility with different aspects of crop and livestock production in organic systems. Nutrient supply to crops depends on the use of legumes to add nitrogen to the system and limited inputs of supplementary nutrients, added in acceptable forms. Manures and crop residues are carefully managed to recycle nutrients around the farm. Management of soil organic matter, primarily through the use of short-term leys, helps ensure good soil structure and biological activity, important for nutrient supply, health and productivity of both crops and livestock. Carefully planned diverse rotations help reduce the incidence of pests and diseases and allow for cultural methods of weed control. As a result of the complex interactions between different system components, fertility management in organic farming relies on a long-term integrated approach rather than the more short-term very targeted solutions common in conventional agriculture.     

Hematopoietic cell regulation by Rac1 and Rac2 guanosine triphosphatases

The Rho guanosine triphosphatases (GTPases) Rac1 and Rac2 are critical signaling regulators in mammalian cells. The deletion of both Rac1 and Rac2 murine alleles leads to a massive egress of hematopoietic stem/progenitor cells (HSC/Ps) into the blood from the marrow, whereas Rac1-/- but not Rac2-/- HSC/Ps fail to engraft in the bone marrow of irradiated recipient mice. In contrast, Rac2, but not Rac1, regulates superoxide production and directed migration in neutrophils, and in each cell type, the two GTPases play distinct roles in actin organization, cell survival, and proliferation. Thus, Rac1 and Rac2 regulate unique aspects of hematopoietic development and function.     

Magnetic domain-wall logic

"Spintronics," in which both the spin and charge of electrons are used for logic and memory operations, promises an alternate route to traditional semiconductor electronics. A complete logic architecture can be constructed, which uses planar magnetic wires that are less than a micrometer in width. Logical NOT, logical AND, signal fan-out, and signal cross-over elements each have a simple geometric design, and they can be integrated together into one circuit. An additional element for data input allows information to be written to domain-wall logic circuits.     

Controlled-release insecticide granules, compared with other soil insecticides, for use against the termite, Macrotermes natalensis Haviland, in the establishment of Eucalyptus plantations

Following the banning of DDT and dieldrin, and pending the withdrawal of other organochlorine insecticides in many countries, there is a need to find alternative treatments against termites for the establishment of Eucalyptus forestry plantations. Controlled-release granules (CRG) of carbosulfan, carbofuran and phorate were nearly as effective as chlordane emulsifiable concentrate (0·6 g a.i./tree) in reducing attack on Eucalyptus grandis W. Hill ex Maiden by Macrotermes natalensis Haviland. The optimum application rate of CRG formulations was 1·0 g a.i./tree mixed with the surrounding soil at planting out. Changes in granule size and release rate had no discernable effect on the efficacy of the granules, nor was there any advantage in incorporating part of the dose in the seedling planting medium. Chlorpyrifos CRG was significantly less effective in protecting the trees. There was evidence that under dry soil conditions phorate CRG was ineffective. Of 11 other non-controlled-release insecticides tested, alphamethrin suspension concentrate at 0·1 g a.i./tree was the only non-organochlorine material as effective as the CRG formulations.