Divergent selection of chickens for antibody response to sheep erythrocytes: kinetics of primary and secondary immunizations

Chicks from lines selectively bred for either high or low antibody response post-primary immunization (PPI) to sheep erythrocytes (SRBC) and their reciprocal crosses were immunized intravenously with 0.1 ml of 0.25% SRBC antigen in Trials 1 and 3 and with 0.1 ml of 0.025%, 0.25%, or 25% SRBC antigen in Trial 2. All initial immunizations were made at 35 days of age, and 0.1 ml of 0.25% SRBC booster dose was given 24 days later. Results showed that (a) population differences appeared by day 4 PPI and persisted through day 24 PPI, (b) regardless of population, peak titers occurred at about the same time for primary and secondary immunizations, (c) dosage of antigen influenced differences among populations in antibody response to primary immunization, and (d) both selected lines had similar responses in 2-mercaptoethanol-sensitive and 2-mercaptoethanol-resistant antibodies to primary but not secondary immunization.     

Soil physical characteristics of peat soils

Drainage and intensive use of fens lead to alterations in the physical characteristics of peat soils. This was demonstrated using parameters of water balance (available water capacity) and the evaluated unsaturated hydraulic conductivity. Deriving the distribution of the pore size from the water retention curve was flawed because of shrinkage due to drainage, especially at high soil water potentials. These errors became greater as the peat was less influenced by soil‐genetic processes. The water retention curves (desorption) evaluated in the field and the laboratory satisfactorily corresponded. However, the wetting‐ and drainage‐curves obtained in the field differed up to 30 vol.‐% water content at same soil water potentials. These differences were largely due to a wetting inhibition.     

The phytotoxicity of mercury vapor

Seed germination and early growth were unexpectedly resistant to Hg-vapor at air saturation levels (14 μg L^?1). Among 15 species and cultivars tested, inhibition of shoot or root growth in excess of 50% was not seen, but occasional stimulation was noted. During extended (70 to 75 days) cultivation at Hg-vapor saturation, inhibitory effects on growth increased with time, and later effects on abscission and necrosis were more severe. Seven days exposures confirmed juvenile resistance at air saturation levels and mature plant sensitivity, expressed by massive abscission at 0.05 μg L^?1. It is suggested that Hg-vapor accelerates senescence-related processes via elevated ethylene production. Evidence suggests that elemental Hg, not ionic Hg, is the active toxicant. An ecophysiological role for Hg-vapor in volcanically active regions is suggested.     

Isolation and propagation of a human enteric coronavirus

Coronavirus-like particles were found by electron microscopy in stools from infants with necrotizing enterocolitis. Stool samples from these infants as well as control specimens were passaged in cultures of human fetal intestinal organs. Two samples yielded virus-like particles and these have now been passaged 14 times (HEC 14). Gradient-purified HEC 14 strains had typical coronavirus morphology on electron microscopy and contained five major proteins with molecular sizes ranging from 190 to 23 kilodaltons. Infants with necrotizing enterocolitis developed specific antibody to the viral antigens between the acute and convalescent stages of the disease, as shown by examining serum specimens by single radial hemolysis, immunoenzymatic assay, and Western immunoblotting. No cross-reactivity was shown with other coronavirus strains tested, or with the newly isolated viruses of the Breda-Berne group, responsible for calf or horse diarrhea.     

Structure determination of partially deuterated carotenoids from intrinsically labeled vegetables by HPLC-MS and 1H NMR

The structures of biosynthetic deuterated carotenoids in labeled vegetables were investigated: (all-E)-lutein and (all-E)-beta-carotene from spinach, and (all-E)-beta-carotene and (all-E)-alpha-carotene from carrots. The vegetables were grown hydroponically using a nutrient solution enriched with deuterium oxide (D(2)O) and were extracted using matrix solid-phase dispersion (MSPD). Deuterium enrichment in the carotenoid molecules was determined by liquid chromatography-mass spectrometry (LC-MS). (all-E)-Lutein and (all-E)-beta-carotene in spinach showed partial deuteration from (2)H(1) to (2)H(12), with the abundance maximum at (2)H(5). (all-E)-beta-Carotene and (all-E)-alpha-carotene from carrots showed partial deuteration from (2)H(1) to (2)H(17), with the abundance maximum at (2)H(11). The (1)H NMR spectra of the four deuterated carotenoids showed additional signals for all methyl groups and decreased signal intensity for the olefinic protons and the methylene protons in the ring. These differences are due to isotopic effects and are based on the substitution of protons by deuterium atoms. The deuteration was distributed randomly throughout the carotenoid molecules.     

Allele distributions of two novel SNPs within the sheep Cyp19 gene

Oestrogen is an important regulator of reproduction and growth. The key enzyme of oestrogen biosynthesis, aromatase cytochrome P450, is encoded by the Cyp19 gene. In order to generate genetic markers for the sheep Cyp19 gene, two novel single nucleotide polymorphisms (SNPs), one located in promoter 2 (P2), the other one in intron 9 (I9), were identified by a comparative sequencing approach. The allele distributions of both SNPs were investigated by means of Polymerase chain reaction‐restriction fragment length polymorphism analysis (PCR‐RFLP) in five economically relevant sheep breeds (British Milk Sheep, Carranzana, Latxa Black Face, Latxa White Face, Merino) and three ancient Hungarian breeds kept as gene reserves (Cikta, Racka, Tsigai). In British Milk Sheep, only the intronic SNP was present whereas in Merino, Cikta, Racka, Tsigai, Carranzana, Latxa Black Face and Latxa White Face, both SNPs could be found. This indicates that the newly identified SNPs can be used as markers for the Cyp19 locus in various sheep breeds.     

Diffusible Factors Essential for Epidermal Cell Redifferentiaion in Catharanthus roseus

During postgenital tissue fusions, some plant epidermal cells redifferentiate into parenchyma, a different cell type. Diffusible factors cause this response in the fusing gynoecium of the Madagascar periwinkle (Catharanthus roseus). Surgical manipulations of the gynoecium showed that epidermal cells from normally nonfusing surfaces could trasmit and respond to the diffusible factors. Furthermore, the diffusible fators could be trapped in agar-impregnated barriers, as shown by the redifferentiation of carpel epidermal cells from nonfusing regions when the factor-loaded barriers were appressed to them.