Successful Induction of Antisera Against Rabbit Embryos for Isolation of the ICM and Putative Embryonic Stem Cells

In Expt 1, goat antisera against rabbit blastocysts were induced using spleen cell injection and skin-graft for immunosurgical isolation of ICM cells. Goats received rabbit spleen cell suspension (4 × 10⁸ cells/ml) intravenously once a week for three consecutive weeks, plus an additional dose (boost injection) 10 days after the third injection, or a piece of rabbit skin (3 × 3 cm) transplantation. Blood samples were collected starting from the day after the last cell injection for 21 days. Serum was separated, heat inactivated and stored in frozen condition before titre analysis. Results showed that the antisera/antibodies derived by spleen cell injection reached their peak titre 7 days after the last cell injection, compared with 5 days by the skin-grafted group. In Expt 2, morphologically normal blastocysts were collected for isolating ICMs immunosurgically or for direct culture of zona-free whole blastocysts. In both methods, ICM cells started attaching to the feeder layer and outgrowing from the centre portion of the cells on day 3 after the onset of culture. ICM outgrowths increased in size during days 4–5, and most cells differentiated morphologically after day 6. One colony derived from isolated ICM developed into morphologically ES-like cells expressing alkaline phosphatase activity. Our results indicated that both skin-grafting and spleen cell injection were effective inducing antisera against rabbit embryonic cells. More studies are required to optimize the culture system for rabbit ES cells.     

The 18O/16O and 17O/16O ratios in atmospheric nitrous oxide: A mass-independent anomaly

Measurements of the oxygen isotope ratios (18O/16O and 17O/16O) in atmospheric nitrous oxide (N2O) from La Jolla, Pasadena, and the White Mountain Research Station (elevation, 3801 meters) in California and the White Sands Missile Range in New Mexico show that N2O has a mass-independent composition. These data suggest the presence of a previously undefined atmospheric process. The La Jolla samples can be explained by a mixing between an atmospherically derived source of mass-independent N2O and biologically derived mass-dependent N2O. Possible origins of the mass-independent anomaly in N2O are discussed.     

Peralkaline silicic volcanic rocks in northwestern nevada

Late Tertiary silicic ashflow tuffs and lavas peralkaline in chemical character (atomic Na + K greater than Al), mainly comendites, occur over wide areas in northwestern Nevada and appear to be widespread in southeastern Oregon. Such peralkaline rocks-which are not uncommon in the western United States-and other chemically unusual silicic rocks are found near the margins rather than toward the center of the Great Basin.     

Uptake and continued metabolic activity of azotobacter within fungal protoplasts

Uptake of vegetative cells of Azotobacter vinelandii into protoplasts of the mycorrhizal fungus Rhizopogon sp. can be induced by treatment with polyethylene glycol (molecular weight, 6000). An L-form of the bacteria has been selected for within the differentiated fungal mycelium which is capable of acetylene reduction and nitrogen fixation, as confirmed by nitrogen-15 assays; this allows the fungus to grow on media lacking any combined nitrogen. The fungus grows and reduces acetylene on concentrations of antibiotics that prevent the growth and activity of free-living Azotobacter. Electron microscopy has revealed modified mitochondrial forms or included bacterial L-forms surrounded by an extra fungal membrane within the hyphae of the modified strains. Poly-beta-hydroxybutyric acid, a storage product of Azotobacter cysts, has also been identified in the hyphae. This would appear to be the first report of the transgenosis for acetylene reduction activity and nitrogen fixation into a eukaryote cell.     

Stratiform copper deposit, northern anatolia, Turkey: evidence for early bronze I (2800 B.C.) mining activity

A stratiform, massive copper sulfide deposit with possible gold, silver, and cobalt credits was discovered by a United Nations reconnaissance team in Paleozoic (?) metamorphic terrain of north central Turkey. The deposit, which is of possible volcanigenic exhalative origin, contains evidence of extensive prehistoric underground mining and smelting activity that, based on radiocarbon data, may date to 2800 B.C. (Early Bronze I Age).     

Elemental compositions of comet 81P/Wild 2 samples collected by Stardust

We measured the elemental compositions of material from 23 particles in aerogel and from residue in seven craters in aluminum foil that was collected during passage of the Stardust spacecraft through the coma of comet 81P/Wild 2. These particles are chemically heterogeneous at the largest size scale analyzed ( approximately 180 ng). The mean elemental composition of this Wild 2 material is consistent with the CI meteorite composition, which is thought to represent the bulk composition of the solar system, for the elements Mg, Si, Mn, Fe, and Ni to 35%, and for Ca and Ti to 60%. The elements Cu, Zn, and Ga appear enriched in this Wild 2 material, which suggests that the CI meteorites may not represent the solar system composition for these moderately volatile minor elements.     

Exogenous polyunsaturated fatty acids (PUFAs) influence permeability,antimicrobial peptide resistance,biofilm formation and membrane phospholipid structure in an A-layer and non-A-layer strain of Aeromonas salmonicida

Aeromonas salmonicida is a Gram-negative bacterium that can infect a wide host range of fish populations, including salmonids and non-salmonids as well as freshwater and marine life. Some strains of A. salmonicida cause the disease furunculosis, which can cause lethargy, intestinal inflammation, ulcers, haemorrhaging and death. The infection is spread through fish-to-fish contact, and the presence of infection can have devastating effects on cultivated fish populations. The purpose of this study was to explore the ability of non-A-layer and A-layer A. salmonicida strains to incorporate polyunsaturated fatty acids (PUFAs) into their lipid profile and test the phenotypic effects thereof. Lipids were extracted from PUFA-exposed cultures and analysed for lipid modification by thin-layer chromatography and ultraperformance liquid chromatography-mass spectrometry, showing A. salmonicida, regardless of A-layer, capable of incorporating all seven of the PUFAs studied. Phenotypic effects were determined through the use of assays that tested for biofilm formation, membrane permeability and cyclic peptide susceptibility. Temperature-dependent effects on biofilm formation were observed, and PUFA exposure showed significant (p < .001) increases in membrane permeability as tested by the uptake of the hydrophobic compounds crystal violet and ethidium bromide. Additionally, some PUFAs elicited modest protection and vulnerability against the membrane-targeting cyclic peptides polymyxin B (PMB) and colistin. The diverse, strain-specific responses to exogenous PUFAs may allude to evolved adaptive strategies that enhance survival, persistence and virulence of non-pathogenic and pathogenic members of bacteria that oscillate between environmental and fish host niches.