Optimizing purebred selection for crossbred performance using QTL with different degrees of dominance

A method was developed to optimize simultaneous selection for a quantitative trait with a known QTL within a male and a female line to maximize crossbred performance from a two-way cross. Strategies to maximize cumulative discounted response in crossbred performance over ten generations were derived by optimizing weights in an index of a QTL and phenotype. Strategies were compared to selection on purebred phenotype. Extra responses were limited for QTL with additive and partial dominance effects, but substantial for QTL with over-dominance, for which optimal QTL selection resulted in differential selection in male and female lines to increase the frequency of heterozygotes and polygenic responses. For over-dominant QTL, maximization of crossbred performance one generation at a time resulted in similar responses as optimization across all generations and simultaneous optimal selection in a male and female line resulted in greater response than optimal selection within a single line without crossbreeding. Results show that strategic use of information on over-dominant QTL can enhance crossbred performance without crossbred testing.     

Cell wall residues in yeast protoplast preparations

Protoplast preparations made from Saccharomyces cerevisiae by prolonged treatment with snail digestive juice contained fibrils and chitinous bud-scar residues from the original cell wall.     

Comparative studies of hepatotoxicity and fumonisin B1 and B2 content of water and chloroform/methanol extracts of Fusarium moniliforme strain MRC 826 culture material

Fusarium moniliforme has been associated with several diseases including equine leukoencephalomalacia, human esophageal cancer and hepatotoxicity/hepatocarcinogenicity in laboratory animals. The potential health risks to animals and humans posed by F. moniliforme contaminated grains cannot be assessed until the toxins are identified and toxicologically evaluated. As part of a systematic approach to identifying the hepatotoxins produced by F. moniliforme, diets containing aqueous and chloroform/methanol (11) extracts of F. moniliforme strain MRC 826 culture material (CM) and/or the extracted CM residues were fed to male Sprague-Dawley rats for four weeks. Serum alanine aminotransferase, aspartate aminotransferase and alkaline phosphatase activities were increased after two and four weeks and microscopic liver lesions were found in those animals fed aqueous CM extract and the CM residue after chloroform/ methanol extraction. Fumonisins B₁ and B₂ were extracted from the CM by water, but not chloroform/ methanol, and were present in the toxic diets at concentrations of 93–139 and 82–147 ppm, respectively. Nontoxic diets contained 22 ppm fumonisin B₁ and 65 ppm fumonisin B₂.Abbreviations CM culture material - ELEM equine leukoencephalomalacia Mention of a trademark, proprietory name or vendor does not imply its approval by the US Department of Agriculture to the exclusion of others that may also be suitable.     

Effect of postnatal development on calcium currents and slow charge movement in mammalian skeletal muscle

Single- (whole-cell patch) and two-electrode voltage-clamp techniques were used to measure transient (Ifast) and sustained (Islow) calcium currents, linear capacitance, and slow, voltage-dependent charge movements in freshly dissociated fibers of the flexor digitorum brevis (FDB) muscle of rats of various postnatal ages. Peak Ifast was largest in FDB fibers of neonatal (1-5 d) rats, having a magnitude in 10 mM external Ca of 1.4 +/- 0.9 pA/pF (mean +/- SD; current normalized by linear fiber capacitance). Peak Ifast was smaller in FDB fibers of older animals, and by approximately 3 wk postnatal, it was so small as to be unmeasurable. By contrast, the magnitudes of Islow and charge movement increased substantially during postnatal development. Peak Islow was 3.6 +/- 2.5 pA/pF in FDB fibers of 1-5-d rats and increased to 16.4 +/- 6.5 pA/pF in 45-50-d-old rats; for these same two age groups, Qmax, the total mobile charge measurable as charge movement, was 6.0 +/- 1.7 and 23.8 +/- 4.0 nC/microF, respectively. As both Islow and charge movement are thought to arise in the transverse-tubular system, linear capacitance normalized by the area of fiber surface was determined as an indirect measure of the membrane area of the t-system relative to that of the fiber surface. This parameter increased from 1.5 +/- 0.2 microF/cm2 in 2-d fibers to 2.9 +/- 0.4 microF/cm2 in 44-d fibers. The increases in peak Islow, Qmax, and normalized linear capacitance all had similar time courses. Although the function of Islow is unknown, the substantial postnatal increase in its magnitude suggests that it plays an important role in the physiology of skeletal muscle.     

Characterization of different B-F (MHC class I) molecules in the chicken

B-F alloantisera recognized distinct 45-Kd molecules on peripheral red blood cells (RBC) from embryonic chickens and heterogeneous molecules of approximately 40 to 44 Kd on peripheral RBC from adult chickens, provisionally referred to as type 1 and type 2, respectively. Type 2 molecules migrated to the basic end of isoelectric focusing gels, exhibited multiple isomorphic variants, and were associated with a smaller polypeptide of approximately 11 to 12 Kd assumed to be beta-2-microglobulin. Type 1 molecules migrated to the acidic end of isoelectric focusing gels, exhibited limited heterogeneity, and were not associated with a smaller polypeptide. Type 1 and type 2 molecules were also shown to be distinct by peptide mapping and serological analyses. In addition, two distinct molecular-weight forms of the type 2 molecules were distinguished, provisionally referred to as 2A (45 Kd) and 2B (42 Kd). In vivo-derived avian erythroblastosis virus (AEV)-transformed erythroleukemia cells expressed type 2A molecules. In vitro-derived AEV-transformed erythroleukemia cells expressed very low levels of B-F molecules; however, they expressed type 2B molecules when induced to differentiate. Normal bursa-derived lymphoid cells expressed type 2A molecules, whereas normal thymus-derived lymphoid cells expressed type 2B molecules. Cloned reticuloendotheliosis virus (REV)-transformed immature lymphoid cells expressed either type 2A or type 2B molecules.     

Natural course of penicillamine nephropathy: a long term study of 33 patients

To elucidate the natural course of the nephropathy associated with penicillamine and thereby facilitate its clinical management 33 patients with rheumatoid arthritis who developed proteinuria during treatment with oral penicillamine were studied in detail throughout their renal illness. Renal biopsies were performed, and creatinine clearance and proteinuria were measured serially for 74 months (range 16-148 months). Fourteen patients developed proteinuria within six months after the start of treatment and 27 within 12 months. When treatment was stopped the proteinuria reached a median peak of 4·2 g/24 h (range 0·3-15·0 g/24 h) at one month (range 0-7 months) before resolving spontaneously by six months (12 patients), 12 months (21), or 18 months (29). In all patients but one, who developed carcinoma of the renal pelvis, proteinuria resolved by 21 months and its median duration was eight months. The median first and last measurements of creatinine clearance showed no appreciable change (80 ml/min and 78 ml/min), and no patient died from or needed treatment for renal failure. The HLA-B8 or HLA-DR3 alloantigen, or both, were identified in 10 patients. Renal biopsy specimens showed membranous glomerulonephritis in 29 patients, minimal change nephropathy in two, and electron dense deposits in the mesangial regions in two.In all the patients whose nephropathy was due solely to treatment with penicillamine the proteinuria resolved completely when the drug was withdrawn; renal function did not deteriorate, and corticosteroids were unnecessary.     

Differential cytotoxicity and mycotoxin content among isolates of Fusarium moniliforme

Curvularia lunata was found causing (disseminated phaeohyphomycosis among a group of Nezara viridula (Insecta:Heteroptera) parasitizing vegetable crop Vigna unguiculata. Dark lesions were seen on pronotum and abdominal sterna. Experimental lesions were produced by applying 0.1 ml of 6.2 × 10⁸cfu/ml^–1 on abdominal sterna. Histopathology revealed that almost all internal organs and tissues showed extensive damage. It is interesting to note that C. lunata exhibited predeliction for chitinous tissues and elicited cellular immune response by granulocytes (phagocytosis). This is the first report of phaeohyphomycosis of an insect, extending the disease to invertebrates.A promising research career of one of the authors (Mrs. Vinita Dubey) was cut short by untimely death. This paper is dedicated to her memory.     

Chicken developmental antigens in 15I5-B-congenic lines

Six partially developed 15I5-B-congenic lines of chickens were used to assess the genetic influence on the developmental expression of selected epitopes of two avian developmental antigen systems: chicken fetal antigen (CFA) and chicken adult antigen (CAA). Both CFA and CAA are serologically and molecularly complex hematopoietic antigen systems, yet little is known about genetic influences on their expression. Using polyclonal rabbit anti-CFA, only slight variations in overall CFA expression on peripheral erythrocytes were observed during neonatal development; no consistent trend was evident. In contrast, analysis with monoclonal antibody 10C6 revealed that the incidence of CFA determinant 8 (CFA8) on erythrocytes of the early neonate was significantly reduced in line 15I5 compared with lines .6-2, .7-2 and .15I-5; line .C-12 also exhibited a reduced CFA8 incidence at hatching. Likewise, the CAA epitope detected by monoclonal antibody 3F12 was found to appear at a slower rate on erythrocytes from lines 15I5 and .C-12 than on those of other lines. Similar results were obtained using the anti-CAA monoclonal 4C2 where reduced expression was found in lines 15I5, .C-12, and .P-13. Results of complement-mediated cytolysis using the positive control 9F9 monoclonal antibody suggested that observed genetic differences were not due to inherent differences in erythroid cytolytic sensitivity. Neither could the results be explained by the incidence of circulating reticulocytes vs. mature erythrocytes within the lines. Rather, the results suggest that different genetic lines of chickens vary in the developmental kinetics of definitive erythrocyte subpopulations bearing specific phenotypes defined by monoclonal antibodies. These findings are discussed in light of previous observations using these B-congenic lines.