Determination of Poly-beta-Hydroxybutyrate and Poly-beta-Hydroxyvalerate in Activated Sludge by Gas-Liquid Chromatography

A convenient gas-liquid chromatography procedure to quantify poly-beta-hydroxybutyrate and poly-beta-hydroxyvalerate in activated sludge was developed by combining lyophilization of the samples, purification of the chloroform phase by water reextraction, and the use of capillary columns. With a flame ionization detector the sensitivity was estimated at 10 g/liter.     

Inhibition of viral mRNA translation in interferon-treated L cells infected with reovirus.

Murine L cells were treated with interferon (IFN) concentrations which reduced by 75 to 80% the synthesis of viral mRNA after infection with reovirus. Protein synthesis was not inhibited in these cells up to 6 h after infection, but a large fraction of the viral mRNA was not associated with polyribosomes and sedimented at about 50S. In contrast, most of the reovirus mRNA was associated with polyribosomes in control infected cells. This mRNA was of similar size to non-polyribosomal mRNA from IFN-treated cells when analyzed by Northern blot hybridization with a cloned cDNA for the s2 reovirus mRNA, indicating that the non-polyribosomal mRNA was not appreciably degraded. Viral mRNA was labeled with [3H]uridine and the non-polyribosomal mRNA was isolated from IFN-treated cells. This mRNA could quantitatively bind to 80S initiation complexes when incubated in a rabbit reticulocyte cell-free system. These findings indicated that the non-polyribosomal RNA was translatable, but that its binding to functional initiation complexes was inhibited in IFN-treated cells by a discriminatory mechanism, which did not affect translation of cellular mRNA. Previous experiments showed that mRNA is blocked in 48S complexes when the alpha subunit of initiation factor eIF-2 is phosphorylated by the double-stranded RNA-dependent protein kinase induced by IFN. A localized activation of this kinase could explain the block of viral mRNA in 48S complexes. By labeling the phosphoproteins of IFN-treated cells with 32P, eIF-2 (alpha P) was shown to cosediment with non-polyribosomal mRNA, presumably in 48S complexes.     

Structure of the human gamma-fibrinogen gene. Alternate mRNA splicing near the 3' end of the gene produces gamma A and gamma B forms of gamma-fibrinogen

The gamma chain of human fibrinogen exists in 2 nonallelic forms, gamma A and gamma B, which differ only in their carboxyl termini. We have found that only one genomic locus exists for gamma-fibrinogen and that the gamma A and gamma B chains arise by alternate mRNA splicing near the 3' end of this gene. In contrast to the rat gamma B mRNA which is produced by alternate splicing with identical polyadenylation sites, human gamma B is produced when the eighth intervening sequence remains unspliced and a polyadenylation signal within this intron is used. The new carboxyl terminus is 16 amino acids longer than the gamma A protein, and although there is only minimal homology between the rat and human carboxyl termini they share a very high proportion of acidic amino acids.     

Immunocytochemical identification and localization of lipase in cells of the mycelium of Penicillium cyclopium variety

The localization of lipase in cells of the fungus Penicillium cyclopium was investigated. It was shown by differential centrifugation of a homogenate of mycelial cells that the activity of the enzyme is associated with the cell wall. A study of ultrathin sections of mycelium fixed using the method of Zvyagintseva in an electron microscope showed that the final products of lipolytic activity of the enzyme is localized on the cell wall. Antibodies were raised against the purified A and B lipases from P. cyclopium and their specificity was assessed by enzyme-linked immunosorbent assay. The antibody preparation was used in cytochemical investigation by immunogold labelling. This study permits the localization of cell-bound lipase mainly in the cell wall and in the periplasmic space. The identity of the cell-bound lipase with one of the two extracellular lipases is also demonstrated.     

Effects of cover soil stockpiling on plant community development following reclamation of oil sands sites in Alberta

Stockpiling of cover soil can influence vegetation development following reclamation. Cover soil, comprising the upper 15–30 cm of the surface material on sites scheduled for mining, is commonly salvaged prior to mining and used directly or stockpiled for various lengths of time until it is needed. Salvaging and stockpiling causes physical, chemical, and biological changes in cover soils. In particular, stockpiling reduces the availability and vigor of vegetative propagules and seed, and can lead to increases in the abundance of some weedy species. This study uses data from monitoring plots to assess how stockpiling of cover soil impacts plant community development on reclaimed oil sands mine sites in northern Alberta. Development of plant communities differed distinctly between directly placed and stockpiled cover soil treatments even 18 years after reclamation. Direct placement of cover soil resulted in higher percent cover, species richness, and diversity. Nonmetric multidimensional scaling and multiresponse permutation procedure revealed compositional differentiation between the treatments. Indicator species analysis showed that direct placement treatment was dominated by perennial species while grasses and annual forb species dominated sites where stockpiled soil was used. Results indicate that stockpiling leads to slower vegetation recovery while direct placement of cover soil supports more rapid succession (from ruderal and annual communities to perennial communities). In addition, direct placement may be less costly than stockpiling. However, scheduling of salvage and placement remains a challenge.     

Two-liquid-phase slurry bioreactors to enhance the degradation of high-molecular-weight polycyclic aromatic hydrocarbons in soil

High-molecular-weight (HMW) polycyclic aromatic hydrocarbons (PAHs) are pollutants that persist in the environment due to their low solubility in water and their sequestration by soil and sediments. The addition of a water-immiscible, nonbiodegradable, and biocompatible liquid, silicone oil, to a soil slurry was studied to promote the desorption of PAHs from soil and to increase their bioavailability. First, the transfer into silicone oil of phenanthrene, pyrene, chrysene, and benzo[a]pyrene added to a sterilized soil (sandy soil with 0.65% total volatile solids) was measured for 4 days in three two-liquid-phase (TLP) slurry systems each containing 30% (w/v) soil but different volumes of silicone oil (2.5%, 7.5%, and 15% [v/v]). Except for chrysene, a high percentage of these PAHs was transferred from soil to silicone oil in the TLP slurry system containing 15% silicone oil. Rapid PAH transfer occurred during the first 8 h, probably resulting from the extraction of nonsolubilized and of poorly sorbed PAHs. This was followed by a period in which a slower but constant transfer occurred, suggesting extraction of more tightly bound PAHs. Second, a HMW PAH-degrading consortium was enriched in a TLP slurry system with a microbial population isolated from a creosote-contaminated soil. This consortium was then added to three other TLP slurry systems each containing 30% (w/v) sterilized soil that had been artificially contaminated with pyrene, chrysene, and benzo[a]pyrene, but different volumes of silicone oil (10%, 20%, and 30% [v/v]). The resulting TLP slurry bioreactors were much more efficient than the control slurry bioreactor containing the same contaminated soil but no oil phase. In the TLP slurry bioreactor containing 30% silicone oil, the rate of pyrene degradation was 19 mg L(-)(1) day(-)(1) and no pyrene was detected after 4 days. The degradation rates of chrysene and benzo[a]pyrene in the 30% TLP slurry bioreactor were, respectively, 3.5 and 0.94 mg L(-)(1) day(-)(1). Low degradation of pyrene and no significant degradation of chrysene and benzo[a]pyrene occurred in the slurry bioreactor. This is the first report in which a TLP system was combined with a slurry system to improve the biodegradation of PAHs in soil.