Delta-aminolevulinic acid synthetase: induction in embryonic chick liver by glucagon

Glucagon elicits a twofold increase in delta-aminolevulinic acid synthetase activity in the livers of 18-day-old chick embryos. This rise occurs when RNA synthesis is inhibited, but is prevented when protein synthesis is blocked. Cyclic adenosine monophosphate appears not to be involved.     

Recharge in Volcanic Systems: Evidence from Isotope Profiles of Phenocrysts

Strontium isotope ratios measured from core to rim across plagioclase feldspar crystals can be used to monitor changes in the isotope composition of the magma from which they grew. In samples from three magma systems from convergent margin volcanoes, sudden changes in major element composition, petrographic features, and strontium isotope composition were found to correspond to discrete magmatic events, most likely repeated recharge of more mafic magma with lower ratios of strontium-87 to strontium-86 into a crustally contaminated magma.     

Effects of l-Ascorbic Acid, α-Tocopherol and Co-culture on In Vitro Developmental Potential of Porcine Cumulus Cells Free Oocytes

The maturation and developmental potential on cumulus-cell-free oocytes is of great importance theoretically and practically. The present study was to investigate the effects of l -ascorbic acid, α-tocopherol and co-culture on in vitro developmental potential of porcine denuded oocytes (DOs). Porcine DOs were cultured in maturation medium supplemented with vitamin C (0, 50, 100, 250, 500, 750 μM) and vitamin E (0, 10, 20, 50, 100, 250 μ m ), respectively. And they were also co-cultured with dispersed cumulus cells (group CCscoculture), intact cumulus cells oocyte complexes (COCs) (group COCscoculture), and COCs whose oocytes were removed (group OOXcoculture), respectively. After 44 h incubation, the maturation rates, cleavage rates and blastocyst rates after parthenogenetic activation in three experiments mentioned above were collected and analysed, respectively. L -Ascorbic acid promoted porcine DOs in vitro maturation and blastocyt development after parthenogenetic activation while α-tocopherol did not increase the in vitro maturation rates, but improved the blastocyst rate. None of the three co-culture manner promoted the in vitro maturation and the cleavage of porcine DOs after parthenogenetic activation, but all the co-culture manners improved the blastocyst rates. Both Vitamin C and E enhance the in vitro developmental potential of porcine DOs. Co-culture increases the developmental potential of porcine DOs.     

Characterization of Populations of Rhizoctonia solani in Paddy Rice Fields in Côte d'Ivoire

ABSTRACT Isolates of Rhizoctonia solani were obtained from plant and soil samples that had been systematically collected in a field experiment in C?te d'Ivoire to study the diversity of the pathogen and the influence of three different rice rotations on the pathogen population. Characterization by morphology, anastomosis testing, pathogenicity testing, and restriction fragment length polymorphisms (RFLPs) of AT-rich DNA (AT-DNA) showed that there were no differences in isolates from different experimental plots, suggesting that the soil as well as the plant population of the fungus was indistinguishable throughout the experiment and was not influenced by crop rotation. Analysis of AT-DNA showed that the isolates obtained from plant material and one from soil shared a distinct banding pattern, identical with the AT-DNA RFLP obtained for the reference strain of anastomosis group 1 (AG-1). The remaining soil isolates produced a consistent RFLP pattern that was distinct from that of the plant isolates. Morphological characterization of isolates produced two major clusters consisting of the same groups of isolates as found by AT-DNA RFLP. Diversity in morphological characters was much higher in plant than in soil isolates and indicated that the population might consist of several clones. Anastomosis testing revealed that soil as well as plant isolates were able to fuse with the tester strain of AG-1. Significant differences in disease severity were observed between the two groups of isolates in pathogenicity tests on rice plants, with plant isolates being distinctively more virulent.     

Effects of Pasteurella haemolytica lipopolysaccharide on selected functions of bovine leukocytes

Lipopolysaccharide (LPS) was obtained from Pasteurella haemolytica serotype 1, using phenol-water extraction, and was evaluated for its ability to modify the biological activity of bovine leukocytes. The LPS was not toxic to polymorphonuclear leukocytes (PMN). The LPS preparation had little effect on random migration of PMN or mononuclear leukocytes (MNL), but caused a 2.5- to 3- fold increase in migration of cells within a whole peripheral blood leukocyte preparation. Phagocytosis of [125I]-labeled Staphylococcus aureus by PMN decreased with low (2.5 micrograms/10(6) cells) and high (65 micrograms/10(6) cells) concentrations of LPS and increased with moderate concentrations of LPS (5 to 25 micrograms/10(6) cells). The LPS enhanced nitroblue tetrazolium reduction by PMN. Moderate LPS concentrations (25 to 50 micrograms/10(6) cells) were mitogenic for MNL, whereas high LPS concentrations (300 micrograms/10(6) inhibited [3H]thymidine incorporation by MNL.     

Novel genotypes of the subtropical grass Eragrostis curvula for the study of apomixis (diplospory)

The aim of this work was to obtain a series of genetically related lines of Eragrostis curvula with different ploidy levels and reproductive modes, which can be used for the discovery of genes associated to diplospory. E. curvula is a widely cultivated forage grass native to Southern Africa that reproduces naturally by obligate diplosporous apomixis (asexual reproduction by seeds) of the Antennaria type. In vitro culture of immature inflorescences of the apomictic cultivar Tanganyika led to the regeneration of a diploid plant with a particular morphology (plant UNST1122). Embryo sac analysis and progeny tests determined that plant UNST1122 reproduces by sexuality. UNST1122 was cloned by dividing its tillers and a R ₁ generation was obtained from seeds after open pollination among the diploid clones. A set of 500 seeds from a diploid R ₁ plant was treated with colchicine and two plants showing a duplicated chromosome number (2n = 4x = 40) were obtained (plants UNST1112 and UNST1131). Progeny tests using RAPDs indicated that these plants reproduce also by sexuality. The availability of sexual tetraploid genotypes of E. curvula will allow the production of hybrids with new interesting combinations of agronomic traits and the developing of mapping populations segregating for diplospory. Besides, these genetically related plants with different reproduction modes constitutes an excellent model for the identification of gen(es) involved in diplosporous apomixis by mRNA profiling as well as to study the genomic rearrangements and gene expression alterations associated to changes at ploidy levels.     

Increasing soy isoflavonoid content and diversity by simultaneous malting and challenging by a fungus to modulate estrogenicity

Soybeans were germinated on a kilogram-scale, by the application of malting technology used in the brewing industry, and concomitantly challenged with Rhizopus microsporus var. oryzae. In a time-course experiment, samples were taken every 24 h for 10 days, and the isoflavonoid profile was analyzed by RP-UHPLC-MS. Upon induction with R. microsporus, the isoflavonoid composition changed drastically with the formation of phytoalexins belonging to the subclasses of the pterocarpans and coumestans and by prenylation of the various isoflavonoids. The pterocarpan content stabilized at 2.24 mg of daidzein equivalents (DE) per g after ～9 days. The levels of the less common glyceofuran, glyceollin IV, and V/VI ranged from 0.18 to 0.35 mg DE/g and were comparable to those of the more commonly reported glyceollins I, II, and III (0.22-0.32 mg DE/g) and glycinol (0.42 mg DE/g). The content of prenylated isoflavones after the induction process was 0.30 mg DE/g. The total isoflavonoid content increased by a factor of 10-12 on DW basis after 9 days, which was suggested to be ascribable to de novo synthesis. These changes were accompanied by a gradual increase in agonistic activity of the extracts toward both the estrogen receptor α (ERα) and ERβ during the 10-day induction, with a more pronounced activity toward ERβ. Thus, the induction process yielded a completely different spectrum of isoflavonoids, with a much higher bioactivity toward the estrogen receptors. This, together with the over 10-fold increase in potential bioactives, offers promising perspectives for producing more, novel, and higher potency nutraceuticals by malting under stressed conditions.