Low protein

About: Low protein is a research topic. Over the lifetime, 8139 publications have been published within this topic receiving 213225 citations.

Grain Composition and Productivity of Maize Hybrids Derived from the Illinois Protein Strains in Response to Variable Nitrogen Supply

Abstract: The Illinois Long-Term Protein Selection strains of maize (Zea mays L.) have been employed in a variety of studies investigating the genetic and physiological control of maize grain composition. These prior studies, however, have not assessed the grain composition and yield potential of these strains in hybrid combinations with an elite tester, or in response to supplemental N. Our objective was to study the interactive effect of genotype and N supply on productivity and grain quality for hybrids with a wide divergence in grain protein. Hybrids derived from the Illinois Protein Strains were evaluated in a 2-yr field experiment where N rates were varied from 0 to 235 kg ha -1 (in eight 34-kg increments), along with a current commercial hybrid sharing the same female parent (FR1064). The Illinois Protein Strain hybrids produced grain protein concentrations that reflected the strain parents, with all hybrids except Illinois Low Protein showing increased grain protein in response to increasing N supply. Many other strain attributes were also manifested at the hybrid level, including the relative differences in kernel weights and the inverse relationship between grain protein to both starch concentration and grain yield. Nitrogen supply positively enhanced grain yield in all hybrids, primarily by increasing kernel number. Nitrogen supply also impacted the yield-protein relationship by stimulating protein synthesis rather than by inhibiting starch production. These results demonstrate the strong genetic control of grain composition in maize hybrids, which can be modulated by the positive effects of N on reproductive sink capacity and seed protein synthesis.

Newborn screening for homocystinuria: Irish and world experience

Abstract: Newborn screening for cystathionine β-synthase deficiency (homocystinuria; HCU) was started in the late 1960 s using a bacterial inhibition assay (BIA). At least seven countries have either national or regional screening programmes; 12 programmes are known to have discontinued. The worldwide incidence of HCU is approximately 1 in 335,000 but varies from 1 : 65,000 (Ireland) to 1 : 900,000 (Japan). Methodologies include the BIA, one-dimensional or thin-layer amino acid chromatography and, more recently, tandem mass spectrometry. The BIA diagnostic cut off concentration of blood methionine varies from 67 to 270 μmol/l (10–40 mg/l) with a median of 135 μmol/l (20 mg/l). In Ireland, 25 cases of HCU from 19 families have been identified from 1.58 million newborn infants since 1971; 21 cases were detected through the screening programme. Of the four missed cases, three were breast-fed at the time of blood collection and one was pyridoxine responsive. These findings were in broad agreement with the results from five other programmes, in which approximately one in every five cases was missed by the screening programme. Early hospital discharge, low protein intake, high blood methionine cut-off concentration and pyridoxine responsiveness were all identified as contributing to missed cases.