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Carbohydrate and Lipid Metabolism During Germination of Uredospores of Puccinia graminis tritici.

Uredospores of Puccinia graminis (Pers.) tritici (Eriks. and Henn.) were uniformly labeled with (14)C by permitting the host (Triticum aestivum L.) to carry out photosynthesis in (14)CO(2) during the process of spore production by the obligate parasite. The use of (14)C labeled spores provided advantages in a study of the utilization of endogenous substrates at frequent intervals with small amounts of spores under conditions conducive to germination.Because of previous uncertainties about the nature of the substrates of importance to germination, a detailed study of carbohydrate and lipid components, both in the spores and in the germination medium, was made during the first 7 hours after placing the spores on aqueous media. Diethyl ether and 80% ethanol soluble metabolites each constituted approximately 20% of the total spore carbon. During the first hour nearly 60% of the 80% alcohol solubles disappeared from the spores while the total ether soluble material did not change appreciably. A significant part of the 80% ethanol soluble materials appeared in the germination medium.During germination and germ tube extension, there was rapid utilization of trehalose, arabitol and mannitol even though appreciable amounts of these materials were present as exogenous pools in the germination medium. Although the total amounts of ether soluble components did not change as drastically as the carbohydrate fraction, there was extensive utilization of palmitic, oleic, linolenic and 9,10-epoxyoctadecanoic acids.The results indicate that the germination process in spores of obligate parasites is not based solely on the utilization of lipids and some possible roles of the changes in internal and external pools of soluble carbohydrates are discussed.

Journal Article↗

Assimilation spectrum of the yeast Candida utilis 49 used for producing fodder yeast from synthetic ethanol.

Oxidizing and assimilating ability of the yeast Candida utilis 49 was tested with 21 different low-boiling organic compounds which come as components of raw synthetic ethanol. The highest yields of yeast dry weight were obtained with ethanol (72.0%), propanol (48.2%), ethyl acetate (43.4%) and acetic acid (34.2%). To a minor extent, the yeast was capable of utilizing also 2-propanol, butanol and 2-butanol; it oxidized most of the compounds tested.

1-Propanol↗

Fermentation products and plant cell wall-degrading enzymes produced by monocentric and polycentric anaerobic ruminal fungi.

Five anaerobic fungal isolates from the bovine rumen were grown on Coastal Bermuda grass (CBG) leaf blades and monitored over a 9-day period for substrate utilization, fermentation products, cellulase, and xylanase activities. Two of the fungal isolates showed monocentric growth patterns; one (isolate MC-1) had monoflagellated zoospores and morphologically resembled members of the genus Piromyces; the other (isolate MC-2) had multiflagellated zoospores and resembled members of the genus Neocallimastix. Three other isolates (PC-1, PC-2, and PC-3) exhibited polycentric growth and have not yet been described in the literature; these isolates were characterized by differences in morphology. All of the isolates degraded CBG to approximately the same extent (70% [dry weight]) in 9 days. Fermentation product accumulation was concurrent with substrate utilization. The major fermentation products for all isolates were formate, acetate, D-(-)-lactate, L-(+)-lactate, ethanol, carbon dioxide, and hydrogen. Succinate was produced by all cultures, with the exception of MC-1. Fermentation balances revealed different profiles for each isolate. As a group, monocentric isolates produced a greater ratio of oxidized to reduced products when grown on glucose or CBG than did the polycentric isolates, which produced a nearly equal ratio of these products. All isolates exhibited cellulolytic and xylanolytic activities, including endoglucanase, exoglucanase, beta-glucosidase, xylanase, and beta-xylosidase activities. Increasing enzyme activity correlated with the accumulation of fermentation products and substrate utilization. The optimum pH for the enzymatic activity of polycentric isolates was within a more narrow range (pH 6.4 to 7.0) than that of the monocentric isolates (pH 5.5 to 7.5). Activity toward cellulosic substrates was not detected until after the disappearance of reducing sugars. Xylanase activity was found to be five to seven times that of carboxymethyl cellulase activity for all cultures grown on CBG.

Animal Feed↗

Hydrogen and ethanol production from glycerol-containing wastes discharged after biodiesel manufacturing process.

H2 and ethanol production from glycerol-containing wastes discharged after a manufacturing process for biodiesel fuel (biodiesel wastes) using Enterobacter aerogenes HU-101 was evaluated. The biodiesel wastes should be diluted with a synthetic medium to increase the rate of glycerol utilization and the addition of yeast extract and tryptone to the synthetic medium accelerated the production of H2 and ethanol. The yields of H2 and ethanol decreased with an increase in the concentrations of biodiesel wastes and commercially available glycerol (pure glycerol). Furthermore, the rates of H2 and ethanol production from biodiesel wastes were much lower than those at the same concentration of pure glycerol, partially due to a high salt content in the wastes. In continuous culture with a packed-bed reactor using self-immobilized cells, the maximum rate of H2 production from pure glycerol was 80 mmol/l/h yielding ethanol at 0.8 mol/mol-glycerol, while that from biodiesel wastes was only 30 mmol/l/h. However, using porous ceramics as a support material to fix cells in the reactor, the maximum H2 production rate from biodiesel wastes reached 63 mmol/l/h obtaining an ethanol yield of 0.85 mol/mol-glycerol.

Bioreactors↗

Effects of organic solvent vehicles on the viability and morphology of isolated perfused porcine skin.

Although many organic solvents are known to be cutaneous irritants, they are commonly utilized as vehicles in percutaneous absorption and toxicity studies. The isolated perfused porcine skin flap (IPPSF) is an alternative animal model that has been used to study percutaneous absorption and cutaneous toxicity. The purpose of this study was to evaluate the effect of five organic solvents (ethanol, acetone, dimethyl sulfoxide (DMSO), toluene, and cyclohexane) on biochemical viability parameters, vascular response, and epidermal morphology of the IPPSF. Cumulative glucose utilization (CGU), the ratio of lactate production/glucose utilization (L/CGU ratio), and the leakage of lactate dehydrogenase (LDH) were used as biochemical indicators of alterations in glucose metabolism and flap viability. Only ethanol resulted in a statistically significant decrease in the average rate of CGU over the perfusion period. All of the solvent treatments resulted in slight increases in LDH release versus the controls. Vascular resistance (VR) was measured to examine the response of the cutaneous vasculature to these solvents, and most treatments resulted in a decreased VR in the terminal phases of perfusion. Ethanol was the only solvent to cause an apparent increase in terminal VR. Light microscopy demonstrated a moderate increase in intracellular edema in the DMSO, toluene, and acetone flaps. Ultrastructural evaluation showed focal blebbing of the nuclear envelope and vesiculation of the rough endoplasmic reticulum in cells of the stratum basale and stratum spinosum layers with DMSO treatment. The IPPSF allowed the evaluation of subtle biochemical, vascular, and morphological changes associated with non-occlusive topical exposure to these organic solvents. These findings support the necessity of documenting vehicle effects which might mask or otherwise alter subtle, but potentially important, compound-specific responses.

Acetone↗

Bioethanol.

Alternatives to petroleum-derived fuels are being sought in order to reduce the world's dependence on non-renewable resources. The most common renewable fuel today is ethanol derived from corn grain (starch) and sugar cane (sucrose). It is expected that there will be limits to the supply of these raw materials in the near future, therefore lignocellulosic biomass is seen as an attractive feedstock for future supplies of ethanol. However, there are technical and economical impediments to the development of a commercial processes utilizing biomass. Technologies are being developed that will allow cost-effective conversion of biomass into fuels and chemicals. These technologies include low-cost thermochemical pretreatment, highly effective cellulases and hemicellulases and efficient and robust fermentative microorganisms. Many advances have been made over the past few years that make commercialization more promising.

Biopolymers↗

Production of mannitol and lactic acid by fermentation with Lactobacillus intermedius NRRL B-3693.

Lactobacillus intermedius B-3693 was selected as a good producer of mannitol from fructose after screening 72 bacterial strains. The bacterium produced mannitol, lactic acid, and acetic acid from fructose in pH-controlled batch fermentation. Typical yields of mannitol, lactic acid, and acetic acid from 250 g/L fructose were 0.70, 0.16, and 0.12 g, respectively per g of fructose. The fermentation time was greatly dependent on fructose concentration but the product yields were not dependent on fructose level. Fed-batch fermentation decreased the time of maximum mannitol production from fructose (300 g/L) from 136 to 92 h. One-third of fructose could be replaced with glucose, maltose, galactose, mannose, raffinose, or starch with glucoamylase (simultaneous saccharification and fermentation), and two-thirds of fructose could be replaced with sucrose. L. intermedius B-3693 did not co-utilize lactose, cellobiose, glycerol, or xylose with fructose. It produced lactic acid and ethanol but no acetic acid from glucose. The bacterium produced 21.3 +/- 0.6 g lactic acid, 10.5 +/- 0.3 g acetic acid, and 4.7 +/- 0.0 g ethanol per L of fermentation broth from dilute acid (15% solids, 0.5% H(2)SO(4), 121 degrees C, 1 h) pretreated enzyme (cellulase, beta-glucosidase) saccharified corn fiber hydrolyzate.

Acetic Acid↗

Purification of transforming growth factor type e.

Transforming growth factor type e (TGFe) is a heat- and acid-stable polypeptide with an apparent molecular weight of 22,000, which stimulates the proliferation of certain epithelial and mesenchymal cells in monolayer and soft agar. TGFe has been purified to homogeneity. Initial acid-ethanol extraction of bovine kidney was followed by batch ion-exchange chromatography utilizing Bio Rex 70 resin. The activity eluted from the Bio Rex 70 resin was concentrated and diafiltered using an Amicon concentrator equipped with an S1Y10 spiral membrane, then was further purified by Bio-Gel P-60 molecular sieve chromatography. Active fractions from molecular sieve chromatography were pooled and purified by heparin-Sepharose affinity chromatography, followed by reverse-phase high-performance liquid chromatography using a microbore C-8 column. The final purification step involved electro-elution of TGFe separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Purity of TGFe was assessed to be greater than 90%.

Animals↗

Isolation and expression analysis of two yeast regulatory genes involved in the derepression of glucose-repressible enzymes.

Yeast strains carrying one of the two regulatory mutations cat1 and cat3 are defective in derepression of several glucose-repressible enzymes that are necessary for utilizing non-fermentable carbon sources. Hence, these strains fail to grow on ethanol, glycerol or acetate. The synthesis of isocitrate lyase, malate synthase, malate dehydrogenase and fructose-1,6-bisphosphatase is strongly affected in cat1 and cat3 strains. Genes CAT1 and CAT3 have been isolated by complementation of the cognate mutations after transformation with an episomal plasmid gene library. The restriction map of CAT1 proved its allelism to the earlier isolated SNF1 gene. Both genes appear to exist as single-copy genes per haploid genome as indicated by Southern hybridization. Northern analysis has shown that the 1.35 kb CAT3 mRNA is constitutively expressed, independent of the carbon source in the medium. Derepression studies with CAT3 transformants using a multi-copy plasmid showed over-expression of glyoxylate cycle enzymes. This result would be consistent with a direct effector function for the CAT3 gene product.

Crosses, Genetic↗

Thiorhodococcus minus, gen. nov., sp. nov., A new purple sulfur bacterium isolated from coastal lagoon sediments.

A new marine phototrophic purple sulfur bacterium (strain CE2203) was isolated in pure culture from a man-made coastal lagoon located on the Atlantic coast (Arcachon Bay, France). Single cells were coccus-shaped, did not contain gas vesicles, and were highly motile. Intracellular photosynthetic membranes were of the vesicular type. Bacteriochlorophyll a and carotenoids of the normal spirilloxanthin series were present as photosynthetic pigments. Hydrogen sulfide, thiosulfate, elemental sulfur, and molecular hydrogen were used as electron donors during photolithotrophic growth under anoxic conditions, while carbon dioxide was utilized as carbon source. Acetate, propionate, lactate, glycolate, pyruvate, fumarate, succinate, fructose, sucrose, ethanol, and propanol were photoassimilated in the presence of hydrogen sulfide. During growth on sulfide, elemental sulfur globules were stored inside the cells. Chemotrophic growth under microoxic conditions in the dark was possible. The DNA base composition was 66.9 mol% G+C. Comparative sequence analysis of the 16S rRNA gene confirmed the membership of strain CE2203 in the family Chromatiaceae. Morphological characteristics of strain CE2203 indicated a close affiliation to the genera Thiocystis and Thiocapsa. However, the phylogenetic treeing revealed no closer relationship to Thiocystis spp. than to Thiocapsa roseopersicina or other known members of the Chromatiaceae. Consequently, strain CE2203 is proposed as the type strain of a new genus and species, Thiorhodococcus minus gen. nov., sp. nov.

Bacteriological Techniques↗

In vitro evaluation of floating and drug releasing behaviors of hollow microspheres (microballoons) prepared by the emulsion solvent diffusion method.

Hollow microspheres (microballoons) floatable in JPX III No.1 solution were developed as a dosage form characterized by excellent buoyant properties in the stomach. Microballoons were prepared by the emulsion solvent diffusion method utilizing enteric acrylic polymers codissolved with drug in a mixture of dichloromethane and ethanol. The release properties of five different drugs exhibiting distinct water solubilities (aspirin, salicylic acid, ethoxybenzamide, indomethacin and riboflavin) entrapped within microballoons were investigated. Buoyancy of the microballoons decreased with increasing drug release rate. In the case of aspirin, salicylic acid and ethoxybenzamide, the drug release profiles of microballoons proved a linear relationships by Higuchi plotting. However, indomethacin and riboflavin release profiles did not follow the Higuchi equation. When the loading amount of riboflavin was higher than the solubility in the mixture of dichloromethane and ethanol, the drug release profiles of the microballoons displayed an initial burst release. The insoluble riboflavin in the mixture of dichloromethane and ethanol adsorbed on to the microballoon surface in the crystal state. Such riboflavin crystals were released preferentially at the initial stage of the release test, which was attributable to the initial burst. In addition, by incorporating a polymer such as hydroxypropylmethylcellulose within the shell of microballoons, the release rate of riboflavin from the microballoons could be controlled while maintaining high buoyancy.

Drug Evaluation, Preclinical↗

Metabolic characterization of Lactococcus lactis deficient in lactate dehydrogenase using in vivo 13C-NMR.

The metabolism of glucose by nongrowing cells of Lactococcus lactis strain FI7851, constructed from the wild-type L. lactis strain MG1363 by disruption of the lactate dehydrogenase (ldh) gene [Gasson, M.J., Benson, K., Swindel, S. & Griffin, H. (1996) Lait 76, 33-40] was studied in a noninvasive manner by 13C-NMR. The kinetics of the build-up and consumption of the pools of intracellular intermediates mannitol 1-phosphate, fructose 1,6-bisphosphate, 3-phosphoglycerate, and phosphoenolpyruvate as well as the utilization of [1-13C]glucose and formation of products (lactate, acetate, mannitol, ethanol, acetoin, 2,3-butanediol) were monitored in vivo with a time resolution of 30 s. The metabolism of glucose by the parental wild-type strain was also examined for comparison. A clear shift from typical homolactic fermentation (parental strain) to a mixed acid fermentation (lactate dehdydrogenase deficient; LDHd strain) was observed. Furthermore, high levels of mannitol were transiently produced and metabolized once glucose was depleted. Mannitol 1-phosphate accumulated intracellularly up to 76 mM concentration. Mannitol was formed from fructose 6-phosphate by the combined action of mannitol-1-phosphate dehydrogenase and phosphatase. The results show that the formation of mannitol 1-phosphate by the LDHd strain during glucose catabolism is a consequence of impairment in NADH oxidation caused by a highly reduced LDH activity, the transient production of mannitol 1-phosphate serving as a regeneration pathway for NAD+ regeneration. Oxygen availability caused a drastic change in the pattern of intermediates and end-products, reinforcing the key-role of the fulfilment of the redox balance. The flux control coefficients for the step catalysed by mannitol-1-phosphate dehydrogenase were calculated and the implications in the design of metabolic engineering strategies are discussed.

Anaerobiosis↗

Emergency department management of patients with seizures: a multicenter study.

OBJECTIVES: Patients with seizure disorders are common in the emergency department (ED), yet little is known regarding the management of these patients. This study was performed to define the frequency of patients with seizure disorders in the ED patient population and to determine possible seizure etiologies, characteristics of diagnostic activities, treatments, and dispositions. METHODS: Twelve EDs monitored all patients with a chief complaint related to seizure disorders presenting over 18.25 days (5% of the calendar year) in late 1997. Retrospective chart review was used to gather specific data regarding these consecutive cases. RESULTS: Of the 31,508 patients who presented to these 12 EDs during the study period, 368 (1.2%) had complaints related to seizures. Three hundred sixty-two charts were available for analysis and make up the study population. Two hundred fifty-seven (71%) utilized emergency medical services (EMS) for transport and care. Advanced care, including intravenous access, laboratory work, cardiac monitoring, or oxygen administration, was utilized in 304 (84%) patients. Antiepileptic drugs were given in 199 (55%) patients. Ethanol withdrawal or low antiepileptic drug levels were implicated as contributing factors in 177 (49%) of patients. New-onset seizures were thought to be present in 94 (26%) patients. Status epilepticus occurred in only 21 (6%) patients. Ninety-eight (27%) of all patients were admitted to the hospital. CONCLUSIONS: Patients with presenting complaints related to seizures are frequent in the ED population and make considerable demands on EMS and ED resources. Six percent of patients with seizure-related presentations were in status epilepticus and more than a fourth of all patients required hospitalization.

Adolescent↗

Chromosomal integration of heterologous DNA in Escherichia coli with precise removal of markers and replicons used during construction.

A set of vectors which facilitates the sequential integration of new functions into the Escherichia coli chromosome by homologous recombination has been developed. These vectors are based on plasmids described by Posfai et al. (J. Bacteriol. 179:4426-4428, 1997) which contain conditional replicons (pSC101 or R6K), a choice of three selectable markers (ampicillin, chloramphenicol, or kanamycin), and a single FRT site. The modified vectors contain two FRT sites which bracket a modified multiple cloning region for DNA insertion. After integration, a helper plasmid expressing the flippase (FLP) recombinase allows precise in vivo excision of the replicon and the marker used for selection. Sites are also available for temporary insertion of additional functions which can be subsequently deleted with the replicon. Only the DNA inserted into the multiple cloning sites (passenger genes and homologous fragment for targeting) and a single FRT site (68 bp) remain in the chromosome after excision. The utility of these vectors was demonstrated by integrating Zymomonas mobilis genes encoding the ethanol pathway behind the native chromosomal adhE gene in strains of E. coli K-12 and E. coli B. With these vectors, a single antibiotic selection system can be used repeatedly for the successive improvement of E. coli strains with precise deletion of extraneous genes used during construction.

Anti-Bacterial Agents↗

Enzyme activities of D-glucose metabolism in the fission yeast Schizosaccharomyces pombe.

The activities of key enzymes that are members of D-glucose metabolic pathways in Schizosaccharomyces pombe undergoing respirative, respirofermentative, and fermentative metabolisms are monitored. The steady-state activities of glycolytic enzymes, except phosphofructokinase, decrease with a reduced efficiency in D-glucose utilization by yeast continuous culture. On the other hand, the enzymic activities of pentose monophosphate pathway reach the maximum when the cell mass production of the cultures is optimum. Enzymes of tricarboxylate cycle exhibit the maximum activities at approximately the washout rate. The steady-state activity of pyruvate dehydrogenase complex increases rapidly when D-glucose is efficiently utilized. By comparison, the activity of pyruvate decarboxylase begins to increase only when ethanol production occurs. Depletion of dissolved oxygen suppresses the activity of pyruvate dehydrogenase complex but facilitates that of pyruvate decarboxylase. Acetate greatly enhances the acetyl CoA synthetase activity. Similarly, ethanol stimulates alcohol dehydrogenase and aldehyde dehydrogenase activities. Evidence for the existence of alcohol dehydrogenase isozymes in the fission yeast is presented.

Cell Division↗

A simple fluorometric assay of protoporphyrin in erythrocytes (EPP) as a screening test for lead poisoning.

A simple microfluorometric procedure for the measurement of protoporphyrin in erythrocytes (EPP) is described. The technique, which can be performed in less than 4 minutes with portable equipment, utilizes 40 mul of capillary blood and only one reagent (94 percent acidified ethanol) for the extraction. The results obtained by this micromethod are in close agreement with those of the ethyl acetate/hydrochloric acid double-extraction methods. The EPP concentration increases markedly when the blood lead level is increased, and the test can be used to screen children for lead poisoning. This new micromethod also gives reproducible results when dried blood spots on filter paper are used instead of liquid blood.

Erythrocytes↗

Hydrogen as a substrate for methanogenesis and sulphate reduction in anaerobic saltmarsh sediment.

Hydrogen gas stimulated sulphate reduction in a saltmarsh sediment and the importance of H2 transferred from organotrophic bacteria to the sulphate-reducers is discussed. beta-fluorolactate inhibited sulphate reduction whether lactate, ethanol or hydrogen was being used as growth substrate. When added to sediment beta-fluorolactate inhibited sulphate reduction with a consequent increase in methane production. Addition of H2 stimulated methanogenesis in sediment and this stimulation was greater if CO2 was also present. Hydrogen availability was the primary limitation of methanogenesis but the low concentration of dissolved CO2 in seawater may limit methane production even if H2 is available. The removal of inhibition of methanogenesis by the use of fluorolactate to suppress sulphate reduction or by the provision of hydrogen indicates competitive inhibition of methanogens by sulphate reducers utilizing transferred hydrogen.

Desulfovibrio↗

Increased NADPH- and NADH-dependent production of superoxide and hydroxyl radical by microsomes after chronic ethanol treatment.

There is increasing evidence that elevated production of reactive oxygen intermediates may contribute to the hepatotoxic actions of ethanol. Microsomes from ethanol-treated rats have been shown to generate oxygen radicals at elevated rates. Most of these studies have utilized chemical analysis techniques to assay for the production of reactive oxygen intermediates. Experiments employing the spin-trapping ESR spectroscopy technique were carried out for a more definitive characterization of production of reactive oxygen intermediates such as superoxide and hydroxyl radical (.OH) by microsomes from ethanol-fed rats and pair-fed controls, in the presence of either NADPH or NADH as the microsomal reductant. Superoxide production was determined by assaying the superoxide dismutase-sensitive generation of stable nitroxyl radical from 1-hydroxy-2,2,6,6-tetramethyl-4-oxo-piperidine resulting from hydrogen abstraction by superoxide radical, while .OH production was determined by assaying the formation of the POBN-alpha-hydroxyethyl radical adduct resulting from addition of the hydroxyethyl radical produced by hydrogen abstraction by .OH. Microsomes from ethanol-treated rats displayed elevated rates of superoxide production with NADPH (50%) as well as with NADH (34%). With both microsomal preparations, the NADPH-dependent rates were three- to fourfold greater than the NADH-dependent rates. Microsomes from the ethanol-treated rats also displayed elevated rates of .OH production (POBN-HER adduct formation) with NADPH (74%) and NADH (52%). With both microsomal preparations, NADPH-dependent rates were equivalent to the rates with NADH. The increase in superoxide and .OH production after ethanol treatment was highly significant (n = 6, P < 0.001). Production of the POBN-HER adduct was sensitive to catalase, mannitol, and GSH, but not to superoxide dismutase. Addition of desferrioxamine caused a marked decrease in the signal intensity; the POBN-HER adduct formed under these conditions most likely reflects the previously reported radical-independent, direct oxidation of ethanol by cytochrome P450. Signal intensity in the presence of desferrioxamine was about threefold higher after ethanol treatment. These results demonstrate that production of reactive oxygen intermediates by microsomes, as determined by ESR spectroscopy, is elevated after chronic ethanol consumption, and that increases in production of reactive oxygen intermediates can be found with NADPH as well as NADH as the microsomal reductant.

Alcoholism↗