The invention related to method and systems for the determination of alteration of gene expression in M. capsulatus under a variery of conditions. A preferred embodiment of the invention relates to micro arrays comprising polynucleotides or oligonucleotides representative for a selective number of the genes of M. capsulatus.

Isocitrate dehydrogenase (IDH) catalyses the dehydrogenation and decarboxylation of isocitrate to alpha-ketoglutarate and CO(2) with NAD or NADP as cofactor. IDH from Aeropyrum pernix is the most thermostable IDH identified. Crystals of A. pernix IDH diffracted to 2.6 A with synchrotron radiation and belong to space group P4(3)2(1)2. IDH from Thermotoga maritima is the only IDH that has been characterized as homotetrameric and might be an evolutionary link between two different IDH subfamilies. T. maritima IDH crystals diffracted to 2.8 A with Cu Kalpha radiation and belong to space group P2(1)2(1)2(1). The structures will be helpful in the study of the factors responsible for thermostability and the evolutionary relationships of IDHs.

The role of Asp-328 and Ile-329 as a cofactor discrimination site of the NAD-dependent isocitrate dehydrognase (NAD-IDH) from Pyrococcus furiosus has been verified by replacing these residues with Lys and Tyr, respectively, which are the corresponding residues in NADP-IDH from Escherichia coli. The Asp-328–Lys mutant showed dual coenzyme specificity, whereas introduction of the double mutation, Asp-328–Lys/Ile-329–Tyr shifted the cofactor preference from NAD to NADP. NADP-dependent P. furiosus IDH retained thermostability and thermoactivity compared with NAD-IDH.

The genes encoding the α- and β-subunits of dissimilatory sulfite reductase, dsrAB, from the hyper-thermophilic archaeon Archaeoglobus profundus and the thermophilic gram-positive bacterium Desulfotomaculum thermocisternum were cloned and sequenced. The dsrAB genes are contiguous, and most probably comprise an operon also including a dsrD homolog, a conserved gene of unknown function located downstream of dsrAB in all four sulfate reducers so far sequenced. Sequence comparison confirms that dissimilatory sulfite reductase, Dsr, is a highly conserved enzyme. A phylogenetic analysis using the available Dsr sequences, including Dsr-like proteins from nonsulfate reducers, suggests a paralogous origin of the α- and β-subunits. Furthermore, the Dsr from sulfate reducers forms a separate cluster, with Dsr from the bacterial sulfate reducers Desulfotomaculum thermocisternum and Desulfovibrio vulgaris branching together, next to Dsr from Archaeoglobus profundus and Archaeoglobus fulgidus. Based on an alignment with the assimilatory sulfite reductase from Escherichia coli, the amino acid residues involved in binding of sulfite, siroheme, and [Fe4S4]-clusters have been tentatively identified, which is consistent with the binding of two sirohemes and four [Fe4S4]-clusters per α2β2 structure. The evolution of Dsr and the structural basis for the binding of substrate and cofactors are discussed.

A thermostable l-malate dehydrogenase from the hyperthermophilic sulfate-reducing archaeon Archaeoglobus fulgidus was isolated and characterized, and its gene was cloned and sequenced. The enzyme is a homodimer with a molecular mass of 70 kDa and catalyzes preferentially the reduction of oxaloacetic acid with NADH. A. fulgidus L-malate dehydrogenase was stable for 5 h at 90 degrees C, and the half-life at 101 degrees C was 80 min. Thus, A. fulgidus L-malate dehydrogenase is the most thermostable L-malate dehydrogenase characterized to date. Addition of K2HPO4 (1 M) increased the thermal stability by 40%. The primary structure shows a high similarity to L-lactate dehydrogenase from Thermotoga maritima and gram-positive bacteria, and to L-malate dehydrogenase from the archaeon Haloarcula marismortui and other L-lactate-dehydrogenase-like L-malate dehydrogenases.

NADP+-specific glutamate dehydrogenase (EC 1.4.1.4) was purified to homogeneity from the extremely thermophilic, strictly anaerobic, sulfate-reducing archaeon Archaeoglobus fulgidus strain 7324. The native enzyme (263 kDa) is composed of subunits of mol. mass 46 kDa, suggesting a hexameric structure. The temperature optimum for enzyme activity was > 95 degrees C. The enzyme was highly thermostable, having a half-life of 140 min at 100 degrees C. Potassium phosphate, KCl, and NaCl enhanced the thermal stability and increased the rate of activity three- to fourfold. The N-terminal 26-amino-acid sequence showed a high degree of similarity to glutamate dehydrogenases from Pyrococcus spp. and Thermococcus spp.

A thermostable homodimeric isocitrate dehydrogenase from the hyperthermophilic sulfate-reducing archaeon Archaeoglobus fulgidus was purified and characterized. The mol. mass of the isocitrate dehydrogenase subunit was 42 kDa as determined by SDS-PAGE. Following separation by SDS-PAGE, A. fulgidus isocitrate dehydrogenase could be renatured and detected in situ by activity staining. The enzyme showed dual coenzyme specificity with a high preference for NADP+. Optimal temperature for activity was 90 degrees C or above, and a half-life of 22 min was found for the enzyme when incubated at 90 degrees C in a 50 mM Tricine-KOH buffer (pH 8.0). Based on the N-terminal amino acid sequence, the gene encoding the isocitrate dehydrogenase was cloned. DNA sequencing identified the icd gene as an open reading frame encoding a protein of 412 amino acids with a molecular mass corresponding to that determined for the purified enzyme. The deduced amino acid sequence closely resembled that of the isocitrate dehydrogenase from the archaeon Caldococcus noboribetus (59% identity) and bacterial isocitrate dehydrogenases, with 57% identity with isocitrate dehydrogenase from Escherichia coli. All the amino acid residues directly contacting substrate and coenzyme (except Ile-320) in E. coli isocitrate dehydrogenase are conserved in the enzyme from A. fulgidus. The primary structure of A. fulgidus isocitrate dehydrogenase confirmes the presence of Bacteria-type isocitrate dehydrogenases among Archaea. Multiple alignment of all the available amino acid sequences of di- and multimeric isocitrate dehydrogenases from the three domains of life shows that they can be divided into three distinct phylogenetic groups.

A novel gram-negative, thermophilic, acetate-oxidizing, sulfate-reducing bacterium, strain A8444, isolated from hot North Sea oil field water, is described. The rod-shaped cells averaged 1 μm in width and 2.5 μm in length. They were motile by means of a single polar flagellum. Growth was observed between 44 and 74°C, with an optimum at 60°C. Spores were not produced. Sulfate and sulfite were used as electron acceptors. Sulfur, thiosulfate, nitrate, fumarate, and pyruvate were not reduced. In the presence of sulfate, growth was observed with acetate, lactate, pyruvate, butyrate, succinate, malate, fumarate, valerate, caproate, heptanoate, octanoate, nonadecanoate, decanoate, tridecanoate, pentadecanoate, palmitate, heptadecanoate, stearate, and ethanol. Pyruvate, lactate, and fumarate did not support fermentative growth. Cytochromes of the c-type were present. Desulfoviridin, desulforubidin, P582, and desulfofuscidin were not present. The G+C content of the DNA was 51 mol%. Sequence analysis of 16S rDNA showed that phylogenetically strain A8444 belongs to the delta subdivision of the Proteobacteria. The closest relatives are Desulfacinum infernum and Syntrophobacter wolinii. Strain A8444 is described as the type strain of the new taxon Thermodesulforhabdus norvegicus gen. nov., sp. nov.

Summary Sulfate-reducing bacteria (SRB) have been isolated from hot oilfield watersfrom subsea oil reservoirs in the North Sea. Experiments with these bacteria ina reservoir simulator indicate that SRB may maintain their activity in theconditions found in most North Sea reservoirs and, if precautions are nottaken, may contribute to souring of the oil and gas. precautions are not taken, may contribute to souring of the oil and gas. Introduction Water flooded hydrocarbon reservoirs may offer good conditions for growth ofthe anaerobic SRB that produce toxic and give H2S. This is particularly thecase for offshore oil fields where oxygen-scavenged seawater with high sulfateconcentration (28 mM) is injected and mixed with the in-situ reservoir porewater containing different kinds of short-chained organic acids. For continuingmicrobial activity, however, both chemical and physical requirements must bemet. Hence, the SRB must be able to grow and generate H2S at the in-situpressures and temperatures in the reservoir. Reservoir conditions weresimulated with a flow rig and investigated with respect to SRB growth andactivity. This flow rig may simulate conditions in a reservoir down to 15,000ft [4.6km], corresponding to a geostatic pressure of 15,000 psi [100 MPa] and atemperature up to 248 degs F [120 degs C]. Spore-forming thermophilic SRB ofthe genus Desulfotomaculum were isolated from hot produced water on different North Sea oil platforms. The bacteria were injected into brine-saturatedsandstone cores inside the rig's pressure vessel. Thereafter, the cores withbacteria were gradually exposed to increasing temperature and pressure, and the SRB activity at the various combinations of high temperature and pressure wasmeasured as sulfate reduction rate. Results showed that the bacteria wereactive and produced H2S to a temperature of 176 degs F [80 degs C] and apressure of 4,500 psi [30 MPa]. Electron micrographs revealed bacterial growthon mineral surfaces. Slimy extracellular material was observed in connectionwith the settlement of the bacteria. Seawater injection often is used in therecovery of hydrocarbons from subsea oil reservoirs. To obtain a successfulrecovery, the microbiological aspects of the waterflood must also beconsidered. Failure to do so may result in severe production problems. Bacterial activity downhole and in the reservoir formation results in formationdamage by loss of reservoir production performance, by a reduction in oilquality, by souring of the off, and by the development of major corrosionproblems, in both injection and production wells. H2S also is poisonous ifinhaled and may present a health hazard for platform personnel. Naturalseawater contain several types of platform personnel. Natural seawater containseveral types of slime-forming and filamentous bacteria, among them SRB andiron-oxidizing bacteria. Under favorable conditions, it is likely that theseorganisms will colonize the huge surface of the reservoir matrix. Theavailability of nutrients is important in the development of a microbialcommunity. The best nutrient conditions for SRB are expected to occur in themixing zone between the injection and formation water. This mixing zonecontains a high concentration of sulfate from seawater and soluble organiccompounds from the formation water. If chemical and physical requirements aremet in such an anaerobic environment, the bacteria will be active and produce H2S. Although SRB activity has been known for decades, little is known abouttheir ability to be active under the extreme pressure and temperatureconditions found in oil reservoirs.. In North Sea reservoirs, pressure commonlyranges from 3,000 to 7,500 psi [20 to 50 MPa] and temperatures from 140 to 212degs F [60 to 100 degs C]. The highest at which biological sulfate reductionhas been observed so far is 199 degs F [93 degs C] by the bacteria Archaeoglobus fulgidus. Other thermophilic SRB are Thermodesulfobacteriummobile and Thermodesulfobacterium commune, with maximum temperature of 180 degsF [85 degs C], and Desulfotomaculum nigrificans, with a maximum temperature of158 degs F [70 degs C]. In this study, we simulated an oil reservoir in alaboratory flow rig, using realistic temperatures and pressure. Representativethermophilic SRB, isolated from hat produced water on North Sea oil platforms, are used to study the effect of these bacteria on the platforms, are used tostudy the effect of these bacteria on the reservoir. Technical Procedure Core Preparation. The cores used in this study were drilled from a matrixblock of the eolic Hopeman sandstone. The block was obtained from an outcrop at Elgin in Scotland, the Clashach quarry. Petrographic and mineralogical studiesof the sandstone indicate Petrographic and mineralogical studies of thesandstone indicate a rather pure (91 %) quartz composition and only traceamounts of clay (muscovite). Grain sizes are on the order of 0.25 mm, with onlysmall variations. The average porosity is 18%, and the permeability ranges from700 to 800 md. Average pore diameter (26 m) was measured by mercury injection. Cylindrical cores 2.0 in. [5.1 cm] in diameter were drilled with length from 4to 30 in. [10 to 80 cm]. All cores were air dried at 176 degs F [80 degs C] for24 hours before cooling and weighing. End caps were mounted and the coresepoxy-coated. The cores were flushed with oxygen-free nitrogen and thenevacuated. This procedure was repeated several time to remove oxygen from themicropores. Several PV's of anaerobic brine containing nutrients for thebacteria were flushed through the cores before they were mounted in the flowrig. To establish a systematical approach, only brine was used to saturate thecore in these experiments. In later experiments, both oil and water wereused. Flow Rig. Fig. 1 illustrates the experimental flow rig. The main componentof the rig is a 3-ft [1-m] -long cylindrical steel pressure vessel with an IDof 2.8 in. [7.1 cm) and a 0.4-in. [1.0-cm] wall thickness. A core prepared asdescribed was pressurized in transformer oil inside the vessel. The rig cansimulate pressure conditions in a reservoir down to 15,000 ft [4 km], corresponding to a geostatic pressure of 15,000 psi [100 MPa]. Pressuretransducers monitored the simulated overburden pressure, water injectionpressure, and the differential pressure across the core. Pumping the fluidagainst a backpressure regulator gave pore pressures up to 10,500 psi [70 MPa]. Experimental flow rates ranged from 0.01 to 9.99 mL/min. A heating cable heatedthe pressure vessel and a thermostat regulated the temperature. Three standardthermocouple K-elements were placed at the inlet, in the middle, and at theoutlet end of the rig. Temperatures up to 248 degs F [120 degs C] could bemaintained with an accuracy of 1.8 degs F [1.0 degs C]. Porosity and Permeability measurements. Average porosity was measured Porosity and Permeability measurements. Average porosity was measured with a Boyle's law porosimeter and checked by measuring the volume of the fluidsaturating the core Dual-piston pumps operating with pulseless constant flowrate were used to inject fluids from a piston-type accumulator cell. Aprogrammable liquid sampler was attached to the outlet end of the programmableliquid sampler was attached to the outlet end of the rig. The differentialpressure across the core, flow-rate measurements, and fluid and corecharacteristics were used in Darcy's equation to calculate permeability.

Using synchronous cultures of the unicellular green alga Chlamydomonas reinhardti, the toxicities of mixtures of Ekofisk crude oil and oil dispersants were measured. Sixteen so-called concentrates and 10 solvent-based dispersants were tested. The dispersing effectiveness of these compounds with respect to the Ekofisk crude oil was also measured. The concentrates were tested undiluted as well as diluted using algal growth medium (2‰ salinity) and artificial sea water (33‰ salinity) as dispersing liquid. The solvent-based compounds were tested in algal medium. For all compounds we found significant correlations between their toxicity and their effectiveness in dispersing the Ekofisk oil, such that the more effective the compound, the more toxic it was.

Urea is accumulated against a concentration gradient in Chlamydomonas reinhardii. Only energy generated from photosynthesis is used for this accumulation, while degradation of urea utilizes other energy sources. Exogenous supplied urea is distributed between two pools, one large nonmetabolic and one metabolic pool. Ammonia inhibits the transport from the nonmetabolic to the metabolic pool.

Marine biofouling, which leads to significant operational stress and economic damage on marine infrastructures, is a major problem in marine related industries. Currently, the most common way to avoid marine biofouling involves the use of biocidal products in surface coatings. However, the need for environmentally friendly antibiofouling compounds has increased rapidly with the recent global prohibition of harmful antifoulants, such as tributyltin (TBT). In particular, periphytic diatoms have been shown to contribute significantly to biofilms, which play an important role in biofouling. Therefore, inhibiting the proliferation of fouling diatoms is a very important step in the prevention of marine biofouling. In this study, we developed a new, rapid, accurate, and convenient growth inhibition assay using the XTT colorimetric method to prevent the growth of the fouling periphytic diatom, Nitzschia amabilis Hidek. Suzuki (replaced synonym, Nitzschia laevis Hustedt). The feasibility of this method was verified by determining the growth inhibition activities of two standard photosynthetic inhibitors, DCMU and CuSO4. However, neither inhibitor had any cytotoxic activities at the range of concentrations tested. Moreover, this method was applied by screening and purification of herbicidic but non-cytotoxic compounds from cyanobacteria extracts. Our results demonstrate the utility of this newly established growth inhibition assay for the identification of marine anti-biofouling compounds.

Synchronization and synchronous growth of a cell wall-less mutant of Chlamydomonas reinhardii have been described. The following growth conditions were used: A modified Sueokas' "high salt minimal medium", 14:10 h light-dark cycle, growth temperature 30 degrees C, light intensity 12-18 Klux and dilution of the culture at the end of the dark to a constant density of 1.0 . 10(6) cells/ml. The time course of increase and distribution of cell volume, cytopla-smic and nuclear division, release of motile cells after the division period and accumulation of DNA, RNA and protein are reported. These mutant cells did not make any sporangium in which the dividing cells were kept as a unit inside a mother cell wall. However, they usually adhered during the period of division, thus making clumps containing 2, 4 and 8 cells. Several of these cell clumps dissolved releasing either single or couples of 2 and 4 cells. After the end of division the cells became fl

Synchronous cultures of Chlamydomonas reinhardii have been examined for the total amounts of carotenoid and chlorophyll present throughout a 12 hrs light–4 hrs dark life cycle. Variations in the carotenoid distribution at different points within the cell cycle have been found. During the greater part of the light period all major carotenoids increased at a proportionally similar rate. However, the increases in lutein and violaxanthin preceded those in β-carotene and neoxanthin by some 2 hrs and that in loroxanthin, an algal xanthophyll, by about 3 hrs. A marked drop in total carotenoid accumulation, corresponding to similar temporary falling away in the accumulation of β-carotene, lutein and violaxanthin occurred at 9 hrs. The correspondence of this with the established drop in RNA accumulation and the break-up of the nucleolus was pointed out. Considerable redistribution among the carotenoids occurred during the dark period, notably the amount of β-carotene increased relative to the total xanthophylls. The full significance of these results can not be estimated in the absence of comparative data on related organisms.

Chemischer InformationsdienstVolume 5, Issue 16 Organic Dyes ChemInform Abstract: LOROXANTHIN FROM CHLAMYDOMONAS REINHARDTI GEORGE W. FRANCIS, GEORGE W. FRANCISSearch for more papers by this authorGJERT KNUTSEN, GJERT KNUTSENSearch for more papers by this authorTORLEIV LIEN, TORLEIV LIENSearch for more papers by this author GEORGE W. FRANCIS, GEORGE W. FRANCISSearch for more papers by this authorGJERT KNUTSEN, GJERT KNUTSENSearch for more papers by this authorTORLEIV LIEN, TORLEIV LIENSearch for more papers by this author First published: April 23, 1974 https://doi.org/10.1002/chin.197416453Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume5, Issue16April 23, 1974 RelatedInformation