Biodegradation of Nitriles in Shale Oil

Enrichment cultures were obtained, after prolonged incubation on a shale oil as the sole source of nitrogen, that selectively degraded nitriles. Capillary gas chromatographic analyses showed that the mixed microbial populations in the enrichments degraded the homologous series of aliphatic nitriles but not the aliphatic hydrocarbons, aromatic hydrocarbons, or heterocyclic-nitrogen compounds found in this oil. Time course studies showed that lighter nitriles were removed more rapidly than higher-molecular-weight nitriles. A Pseudomonas fluorescens strain isolated from an enrichment, which was able to completely utilize the individual nitriles undecyl cyanide and undecanenitrile as sole sources of carbon and nitrogen, was unable to attack stearonitrile when provided alone as the growth substrate. A P. aeruginosa strain, also isolated from one of the enrichments, used nitriles but not aliphatic or aromatic hydrocarbons when the oil was used as a sole nitrogen source. However, when the shale oil was used as the sole source of carbon, aliphatic hydrocarbons in addition to nitriles were degraded but aromatic hydrocarbons were still not attacked by this P. aeruginosa strain.     

Effect of nitrogen nutrition on the concentration of viruses, phospholipids and galactolipids of barley leaves infected with barley stripe mosaic virus (BSMV)

The effect of infection of barley with barley stripe mosaic virus on the chlorophyll, phospholipid and galactolipid content was examined in plants grown in sand culture with a range of nitrogen concentrations. The systemic yellowing and mosaic symptoms of infection were associated with a reduction in the chlorophyll and galactolipid content and an increase in the phospholipid content of leaves. The effects of the virus were not reversed by high nitrogen. The effects of virus infection are interpreted as a stress-induced phenomenon and the effects compared with those brought about by other stresses.     

Polymerase chain reaction-gene probe detection of microorganisms by using filter-concentrated samples.

To detect low levels of microorganisms in environmental samples by using polymerase chain reaction (PCR)-gene probe detection, samples were concentrated by filtration. Fluoropore (Millipore Corp.) filters were compatible with PCR DNA amplification, whereas various other filters including nitrocellulose and cellulose acetate filters inhibited PCR amplification. By concentrating cells on Fluoropore filters and releasing the DNA by freeze-thaw cycling, PCR DNA amplification could be performed without removing the filter. Concentration with Fluoropore FHLP and FGLP filters permitted the detection of single cells of microorganisms in 100-ml samples by PCR-gene probes.     

Developmental potential of rabbit oocyte matured in vitro: the possible contribution of prolactin

The present study was undertaken to define hormonal conditions for in vitro maturation that support subsequent fertilization and embryonic development. Follicular oocytes were recovered from nonstimulated rabbit ovaries and cultured for 12 h in Brackett's medium supplemented with or without hormones. Matured oocytes were inseminated in vitro and transferred 12 h later to Ham's F-10 medium supplemented with 20% fetal calf serum. The initial cleavage frequency of matured oocytes in Brackett's medium was comparable to the frequency of development for in vitro-matured oocytes under various hormonal conditions. However, the addition of estradiol (E2, 1 microgram/ml) to incubation medium containing luteinizing hormone (LH) and follicle-stimulating hormone (FSH) increased significantly (p less than 0.001) the percentage of embryos achieving morula or blastocyst formation (16/98, 16.3%), as compared to the mature oocytes in medium containing LH, LH plus FSH, or no hormone. The addition of prolactin (PRL) to the maturation medium increased the percentage of development to organized embryos in a dose-dependent manner. In vitro-matured oocytes in medium containing LH, FSH, and PRL exhibited a significantly (p less than 0.001) lower incidence of developmental competence (5/95, 5.3%) than oocytes matured in the presence of E2 in conjunction with pituitary hormones (43/89, 48.3%). These results demonstrate that hormonal composition in the environment of the oocyte is critical for acquisition of developmental capacity. PRL as well as E2 appears to be an important constituent in the process of oocyte maturation, promoting preimplantation embryonic development.     

Demonstration of human platelet β-adrenergic receptors using 125I-labeled cyanopindolol and 125I-labeled hydroxybenzylpindolol

The radioiodinated pindolol analogs ¹²⁵I-labeled cyanopindolol ([¹²⁵I]CYP) and ¹²⁵I-labeled hydroxybenzylpindolol ([¹²⁵I]HBP) have been used to study binding to human platelet β-adrenergic receptors. [¹²⁵I]CYP binds to a saturable class of binding sites on platelet membranes with a dissociation constant (K_d) of 14±3 pM and maximal binding capacity (B_max) of 18±4 fmol/mg protein. Binding of [¹²⁵I]CYP is reversible and is characterized by forward and reverse rate constants of 1.8·10⁷ s^?1·M^?1 and 3.8·10^?4 s^?1, respectively. [¹²⁵I]HBP binds to a saturable class of platelet membrane sites with a K_d of 50±10 pM and B_max of 32±6 fmol/mg protein. [¹²⁵I]HBP also binds to a saturable class of sites on intact platelets with a K_d of 58±14 pM and B_max of 24±4 molecules per platelet. Binding of [¹²⁵I]CYP and [¹²⁵I]HBP is stereospecifically inhibited by propranolol and epinephrine; the (?) stereoisomers are at least 50-times more potent than the (+) stereoisomers. Binding of both radioligands is inhibited by adrenergic ligands with a potency order of propranolol ? isoproterenol > epinephrine > practolol > norepinephrine > phenylephrine. These observations indicate that [¹²⁵I]CYP and [¹²⁵I]HBP bind to platelet sites which have the pharmacological characteristics of β-adrenergic receptors but which are not typical of either the β₁ or β₂ sub-type.     

Interaction of fluorescent gonadotropin-releasing hormone with receptors in cultured pituitary cells

A fluorescent derivative of the gonadotropin-releasing hormone (GnRH) agonist analog, [D-Lys6]GnRH, was synthesized for receptor studies and shown to be biologically active. The rhodamine-derivatized peptide (Rh-GnRH) retained 40% of the receptor binding activity of [D-Lys6]GnRH, and 50% of the luteinizing hormone-releasing activity assayed in cultured pituitary cells. The fluorescent analog was employed to visualize the distribution of GnRH receptors in cultured pituitary cells, using the technique of video-intensified fluorescence microscopy. The binding of Rh-GnRH was confined to the large gonadotrophs which comprised 15% of the cell population. The specificity of the binding was shown by the absence of significant fluorescence in the presence of a 100-fold excess of [D-Lys6]GnRH, or when Rh-GnRH was incubated with choriocarcinoma, neuroblastoma, or 3T3 cell lines devoid of GnRH receptors. The interaction of Rh-GnRH with living pituitary cells was characterized by an initial diffuse distribution, followed by the formation of polar aggregates that later appeared to be internalized. These observations emphasize the value of fluorescent derivatives of GnRH for elucidating the course of the interaction with specific receptors on pituitary gonadotrophs. The initial results indicate that GnRH-receptor complexes undergo aggregation during stimulation of luteinizing hormone release, and are later internalized for subsequent degradation and/ or intracellular actions.     

Effects of Temperature and Crude Oil Composition on Petroleum Biodegradation

The biodegradability of seven different crude oils was found to be highly dependent on their composition and on incubation temperature. At 20 C lighter oils had greater abiotic losses and were more susceptible to biodegradation than heavier oils. These light crude oils, however, possessed toxic volatile components which evaporated only slowly and inhibited microbial degradation of these oils at 10 C. No volatile toxic fraction was associated with the heavier oils tested. Rates of oil mineralization for the heavier oils were significantly lower at 20 C than for the lighter ones. Similar relative degradation rates were found with a mixed microbial community, using CO2 evolution as the measure, and with a Pseudomonas isolate from the Arctic, using O2 consumption as the measure. The paraffinic, aromatic, and asphaltic fractions were subject to biodegradation. Some preference was shown for paraffin degradation, especially at low temperatures. Branched paraffins, such as pristane, were degraded at both 10 and 20 C. At best, a 20% residue still remained after 42 days of incubation. Oil residues generally had a lower relative percentage of paraffins and higher percentage of asphaltics than fresh or weathered oil.     

Specific affinity labelling of tubulin with bromocolchicine

Bromocolchicine, synthesized by substituting tho N-acetyl moiety of colchicine with a reactive bromoacetyl group, was found to be an affinity label for tubulin. Binding of [³H]colchicine to tubulin was competitively and irreversibly inhibited by bromocolchicine with a K_i value of 2.3 × 10^?5m. The affinity label could not be displaced by precipitating the protein with trichloroacetic acid and is thus covalently bound. Autoradiographs of brain high-speed supernatant proteins after their electrophoretic separation on sodium dodecyl sulphate/polyacrylamide gels showed that [³H]bromocolchicine reacted with four proteins, of which tubulin was one.Labelling of two of these proteins could be prevented by pretreatment of the brain extracts with α-bromoacetic acid, after which 70% of the covalently bound label was specifically located in the tubulin band. Up to 1.6 mol of affinity label could be bound per mol of tubulin, while under our experimental conditions 1 mol of protein bound irreversibly only 0.2 mol of [³H]colchicine. Autoradiography of sodium dodecyl sulphate/urea-polyacrylamide gels, which separate the subunits of tubulin, showed about 30% [³H] bromocolchicine bound to the α-subunit of tubulin and 70% to tho β-subunit.The irreversible binding site of colchicine was localized to the α-subunit, as labelling of only this subunit was inhibited by colchicine at high affinity label concentrations. At lower concentrations, colchicine inhibited the labelling of both subunits.Bromoacetic acid did not inhibit the reaction of the affinity label with the tubulin subunits, but increased the inhibition of [³H]bromocolchicine binding at lower concentrations of the affinity label in brain extracts preincubated with cold colchicine. This is interpreted to show a conformational change which takes place in the two subunits of tubulin upon binding of colchicine and results in the exposure of some of the binding sites of [³H]bromocolchicine to bromoacetic acid.     

Distribution of Hydrocarbon-Utilizing Microorganisms and Hydrocarbon Biodegradation Potentials in Alaskan Continental Shelf Areas

Hydrocarbon-utilizing microorganisms were enumerated from Alaskan continental shelf areas by using plate counts and a new most-probable-number procedure based on mineralization of ¹⁴C-labeled hydrocarbons. Hydrocarbon utilizers were ubiquitously distributed, with no significant overall concentration differences between sampling regions or between surface water and sediment samples. There were, however, significant seasonal differences in numbers of hydrocarbon utilizers. Distribution of hydrocarbon utilizers within Cook Inlet was positively correlated with occurrence of hydrocarbons in the environment. Hydrocarbon biodegradation potentials were measured by using ¹⁴C-radiolabeled hydrocarbon-spiked crude oil. There was no significant correlation between numbers of hydrocarbon utilizers and hydrocarbon biodegradation potentials. The biodegradation potentials showed large seasonal variations in the Beaufort Sea, probably due to seasonal depletion of available nutrients. Non-nutrient-limited biodegradation potentials followed the order hexadecane > naphthalene pristane > benzanthracene. In Cook Inlet, biodegradation potentials for hexadecane and naphthalene were dependent on availability of inorganic nutrients. Biodegradation potentials for pristane and benzanthracene were restricted, probably by resistance to attack by available enzymes in the indigenous population.