Ammonia-oxidizing bacteria (AOB) are chemolithotrophs that oxidize ammonia/ammonium to nitrite in a two-step process to obtain energy for survival. AOB are difficult to isolate from the environment and iso lated strains may not represent the diversity in soil. A genetic database and molecular tools were developed based on the ammonia monooxygenase (AMO) encoding genes that can be used to assess the diversity of AOB that exist in soil and aquatic environments without the isolation of pure cultures. The amo genes have excellent potential as molecular markers; since AMO is only found in the AOB and is essential for their metabolism, AOB must carry at least one functional copy of the amo operon. The operon is composed of at least three genes, amoC, amoA. and amoB (encoding for the subunits AmoC, AmoA, and AmoB). The amoC gene was first discovered and its sequence was obtained from Nitrosospira sp. NpA V. The amooperon is found in several copies within AOB genomes in the β-subdivision but as a single copy in y-subdivision genomes. In Southern analysis, cross-hybridization was only observed between amo genes within a subdivision. They-subdivision amo sequences have higher identity values to the genes encoding the related particulate methane monooxygenase than to the β-subdivision amo sequences. Since amoA encodes the subunit containing the active site, it was sequenced entirely for all the strains studied (16 amoA sequences total). The amoC and amoB genes were also sequenced for several strains. The amo genes allow for better discrimination between closely related strains than the 16S rRNA genes. In all cases, the amo operon consists of amoC, followed by a variable length intergenic region, and then by amoAB. The variability in length of the intergenic region is strain specific, and is therefore potentially useful for profiling AOB communities. The amo-gene database was the basis for the design of conserved oligonucleotide primers for the polymerase chain reaction (PCR). These primers were used to amplify amo sequences from a mixed template of DNA extracted directly from soil. Results indicate that the amo genes are excellent molecular markers for the assessment of AOB communities in the environment.

No description available.

Eleven gas species, including CO, CO2, H2, H2O, H2S, HCl, NOX, O2, SO2, COS and SO3, were measured in a 150 kWth, staged, pulverized coal, down-fired combustor using a Fourier transform infrared (FTIR) spectrometer, gas chromatograph (GC), and a Horiba PG-250 5-gas analyzer. Additional gases such as HCN, NH3, CH4, and other hydrocarbons were also measured. Seven coals of varying rank and composition were investigated. Measurements were obtained in reducing (S.R. = 0.85) and oxidizing (S.R. = 1.15) conditions. In particular, sulfur- and chlorine-containing species including H2S, SO2, COS, SO3, and HCl are discussed. In the reducing zone, all four measured sulfur species were present although SO3 was only 1-3% of the total coal sulfur. A trade-off between SO2, H2S, and COS was clearly identifiable according to S.R. H2S and COS increased and SO2 decreased in highly reducing or high-CO regions. The total amount of sulfur in the measured species in the reducing zone was estimated to be about 65-80% of the total coal sulfur. The total amount of sulfur measured in the four gases increased linearly with coal sulfur in both the oxidizing and reducing zones for the seven coals considered. In the oxidizing zone, SO3 remained low (1-3% of total sulfur) with the only other measurable sulfur bearing species being SO2. Chlorine was found to be released in the reducing zone and form primarily HCl. As the HCl was transported into the oxidizing region, the chlorine remained as HCl. Measurement of HCl was difficult, making some of the data incomplete. The HCl concentration was found to be affected by the flow rate of gases into the sampling line and gas analyzers suggesting HCl is highly reactive and needs to be quenched rapidly or it will react during sampling. Several trends in the data were matched by equilibrium calculations including trends for H2S, COS and SO2 in both reducing and oxidizing conditions. SO3 did not match equilibrium although the amount of SO3 was proportional to the amount of sulfur in the coal. HCl, though consistent with cited literature for several coals, did not agree with equilibrium trends or values.

Syntrophic relationships between fatty acid degrading bacteria and hydrogenotrophic methanogens are important for a well-functioning anaerobic degradation process during biogas production from organic waste material. This is particularly important in biogas processes fed protein-rich material as their degradation gives rise to high levels of ammonia, which inhibits many microorganisms. A common problem arising in the high-ammonia biogas process is the accumulation of volatile fatty acids, such as acetate, propionate or butyrate, which negatively affects the methane production. The aim of this study was to isolate and identify the syntrophic butyrate-oxidizing bacteria present in the enriched syntrophic communities originating from thermophilic continuously fed laboratory-scale reactors. Butyrate was added to batch assays containing the enrichment cultures. Sequencing of a 464 bp region within the 16S rRNA gene was conducted to study the change in microbial community structure over time during the butyrate degradation. The enrichment culture was also used as an inoculum source during the isolation attempts using agar cultivation, colony transfer and 16S rRNA gene sequencing of the obtained isolates. From the Illumina sequencing data, it could be concluded that the novel species of interest belonged to the genus Syntrophothermus. Two species were isolated, however neither appeared to be the butyrate-degrading bacterium. One of the species was Defluviitoga tunisiensis and the other was a novel species related to the mesophilic bacterium Schnuerera ultunensis.

<p> A textural and mineralogical study of the magnetite, hemoilmenite and minor sulfide phases of the Whitestone anorthosite, Dunchurch, Ontario, was carried out. The composition of magnetite and hemo-ilmenite was determined by chemical analysis, X-ray diffraction and electron probe microanalysis. A modification of the solvus shape in the hematite-ilmenite system consistent with the composition of hemo-ilmenite lamellae, as well as a mechanism for formation of metamorphic magnetite porphyroblasts from ferrianilmenite is proposed. Buddington and Lindsley's experimental data cannot be used directly to obtain f02 and T of formation of the anorthosite because compositions fall in the highly oxidizing and as yet undetermined portion of their diagram. </p> / Thesis / Master of Science (MSc)

京都大学 / 新制・課程博士 / 博士(農学) / 甲第23251号 / 農博第2458号 / 新制||農||1085(附属図書館) / 学位論文||R3||N5341(農学部図書室) / 京都大学大学院農学研究科応用生命科学専攻 / (主査)教授 阪井 康能, 教授 小川 順, 教授 井上 善晴 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

京都大学 / 新制・課程博士 / 博士(農学) / 甲第24679号 / 農博第2562号 / 新制||農||1100(附属図書館) / 学位論文||R5||N5460(農学部図書室) / 京都大学大学院農学研究科応用生物科学専攻 / (主査)教授 澤山 茂樹, 教授 吉田 天士, 准教授 中川 聡 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DGAM

No description available.

No description available.

Menhaden is the major source of fish oil in the United States. Due to a high amount of polyunsaturated fatty acids which are highly susceptible to autoxidation, menhaden oil deteriorates rapidly, leading to objectionable off-odors and off-flavors. The purpose of this study was to investigate if the enzyme lipoxygenase is present in menhaden gill tissue and if it is a contributing factor in menhaden oil oxidation. Peroxide, TBA and anisidine values of undeodorized and deodorized menhaden oils exhibited two maxima during 20 weeks of storage at 30°C. Peroxide values of the undeodorized oil peaked at week 1 with 6.71 meq/kg and at week 12 with 21.50 meq/kg, while in the deodorized oil it peaked at week 8 (9.28 meq/kg) and week 20 (18.71 meq/kg). TBA maxima were observed at week 2 (1416 μMol/kg) and week 12 (4951 μMol/kg) and at week 8 (1397 μMol/kg) and week 20 (4284 μMo/kg) for undeodorized and deodorized menhaden oil respectively. Anisidine values showed maxima at the same weeks. These results indicate that lipid peroxidation of the deodorized oil lagged a few weeks behind the undeodorized oiL In this study, the conjugated diene and fluorescence analyses were found to be poor indicators for monitoring lipid oxidation in menhaden oil. Enzyme assays indicated that lipoxygenase activity is present in menhaden gill tissue with maximum activity at pH 9-10, resembling that of soybean lipoxygenase-l. A sensory panel judged omega-3 fatty acid ester concentrates treated with the enzyme extract as having a significantly (p < 0.03) stronger smell than the control ester for the first four weeks of an eight week study. However, no significant difference was found between the TBA values of the esters. Of the 60 volatile compounds identified by GC-MS in the undeodorized menhaden oil, 19 were aldehydes, 9 were alcohols and 8 were ketones. Volatiles that are potentially Ii poxygenase derived, namely 2-octenal, 1-octen-3-01, 2-nonenal, 2,6-nonadienal (E,Z), and 2,5-octadien-l-ol were among those identified in the undeodorized menhaden oil. The deooorized oil contained fewer total volatiles, and fewer aldehydes (6), ketones (1) and alcohols (8), but more long chain aliphatic compounds such as hydrocarbons, many of which were not possible to positively identify. No lipoxygenase derived volatiles were identified in the deooorized oil. Most of the volatiles in the omega-3 fatty acid ester concentrates were identified as esterified short chain fatty acids. No difference in the amount of total volatiles was found between four esters that were treated with and without the enzyme extract, a boiled enzyme extract and an enzyme extract that was inocculated with esculetin. However, in a repetition of just the control and the enzyme treated ester, a significantly (p < 0.02) higher amount of total volatiles was found in the enzyme treated ester, supporting the results of the sensory analysis. It was not possible to identify specific volatiles in the enzyme treated ester that were present in larger concentrations than in the other ester treatments. Volatiles identified in EPA and DHA ethyl esters were similar to those volatiles found in the undeodorized and deodorized menhaden oil as well as the omega-3 fatty acid ester concentrates, but no lipoxygenase derived volatiles were found. While lipoxygenase activity was found in the gill extract of menhaden, and sensory analysis was able to distinguish between a control and an enzyme incubated oil, the enzymatic activity was low (apparent Km = 16.7 μMol) and volatile analysis of various oils did not support the hypothesis that lipoxygenase is a major contributor to menhaden oil oxidation. Future research should include isolation and purification of menhaden gill lipoxygenase and the study of model systems to develop a better understanding of the contribution of lipoxygenase activity to oxidation of menhaden oil. / Ph. D.