scholarly journals Pathway of Glucose Catabolism by Strain VeGlc2, an Anaerobe Belonging to the Verrucomicrobiales Lineage of Bacterial Descent

1998 ◽  
Vol 64 (12) ◽  
pp. 4830-4833 ◽  
Author(s):  
Peter H. Janssen
Keyword(s):  
Electron Transport ◽  
Enzyme Activities ◽  
The Other ◽  
Difference Spectra ◽  
Glucose Catabolism ◽  
Cell Extracts ◽  
In Vitro Measurements ◽  
End Products ◽  
Reductive Pathway

ABSTRACT Strain VeGlc2, an anaerobic ultramicrobacterium belonging to theVerrucomicrobiales lineage of bacterial descent, fermented glucose to acetate, propionate, succinate, and CO2. The distribution of radiolabel in the fermentation end products produced from position-labelled glucose and in vitro measurements of enzyme activities in crude cell extracts prepared from glucose-grown cells showed that glucose was metabolized via the Embden-Meyerhof-Parnas pathway. The 6-phosphofructokinase (EC 2.7.1.90 ) activity required pyrophosphate as the phosphoryl donor, and ATP could not replace pyrophosphate. The other enzyme activities were those of a classical Embden-Meyerhof-Parnas pathway. 14CO2 was incorporated into propionate and succinate, suggesting that a carboxylation reaction rather than a transcarboxylation reaction was involved in the reductive pathway leading to succinate and propionate. Difference spectra showed that a type b cytochrome was present, which could be involved in electron transport in the reductive pathway.

In vitro measurements of the competitive interactions between two saprobic basidiomycetes on Typha latifolia

2005 ◽  
Vol 83 (11) ◽  
pp. 1523-1527 ◽  
Author(s):  
Michael J. Schulz ◽  
James F. Cahill, ◽  
Randolph S. Currah
Keyword(s):  
Relative Abundance ◽  
Typha Latifolia ◽  
The Other ◽  
Competitive Interactions ◽  
In Vitro Measurements ◽  
Leaf Tissues ◽  
Leaf Segments

Psathyrella typhae (Kalchbr.) Pearson & Dennis forms small basidiomata (mushrooms) and Sclerotium hydrophilum Saccardo in Rothert numerous minute sclerotia at the base of senescent shoots of Typha latifolia L. To assess how the two might compete in nature, isolates of these fungi were paired on autoclaved leaf segments of T. latifolia and incubated at 15 and 25 °C. The relative abundance of each species in the segments was determined by macerating the leaf tissues and then transferring fragments of macerate to microplates containing two types of media: one conclusively demonstrated the presence of P. typhae while the other demonstrated the presence of S. hydrophilum. Relative numbers of microplate wells showing positive reactions for each species on each medium indicated the proportion of the segment occupied following single and paired inoculations. These data demonstrated that competition was asymmetric, with P. typhae the stronger competitor at both temperatures, and uninhibited by the presence of S. hydrophilum. In contrast, S. hydrophilum was competitively excluded by P. typhae.

scholarly journals The separation of β-glucanases produced by Cytophaga johnsonii and their role in the lysis of yeast cell walls

1970 ◽  
Vol 120 (1) ◽  
pp. 67-78 ◽  
Author(s):  
J. S. D. Bacon ◽  
A. H. Gordon ◽  
D. Jones ◽  
Irene F. Tayor ◽  
D. M. Webley
Keyword(s):  
Yeast Cell ◽  
Cell Walls ◽  
Culture Fluid ◽  
The Other ◽  
Yeast Cells ◽  
Wall Structure ◽  
Enzyme Preparations ◽  
End Products ◽  
Isolated Cell

1. When Cytophaga johnsonii was grown in the presence of suitable inducers the culture fluid was capable of lysing thiol-treated yeast cell walls in vitro. 2. Autoclaved or alkali-extracted cells, isolated cell walls and glucan preparations made from them were effective inducers, but living yeast cells or cells killed by minimal heat treatment were not. 3. Chromatographic fractionation of lytic culture fluids showed the presence of two types of endo-β-(1→3)-glucanase and several β-(1→6)-glucanases; the latter may be induced separately by growing the myxo-bacterium in the presence of lutean. 4. Extensive solubilization of yeast cell walls was obtained only with preparations of one of these glucanases, an endo-β-(1→3)-glucanase producing as end products mainly oligosaccharides having five or more residues. Lysis by the other endo-β-(1→3)-glucanase was incomplete. 5. The β-(1→6)-glucanases produced a uniform thinning of the cell walls, and mannan–peptide was found in the solution. 6. These results, and the actions of the enzyme preparations on a variety of wall-derived preparations made from baker's yeast, are discussed in the light of present conceptions of yeast cell-wall structure.

Effects of Carbohydrate Pulses and pH on Population Shifts within Oral Microbial Communities in vitro

1989 ◽  
Vol 68 (9) ◽  
pp. 1298-1302 ◽  
Author(s):  
D.J. Bradshaw ◽  
A.S. McKee ◽  
P.D. Marsh
Keyword(s):  
Microbial Communities ◽  
Carbohydrate Metabolism ◽  
Oral Bacteria ◽  
The Other ◽  
Carbohydrate Availability ◽  
Oral Microflora ◽  
End Products ◽  
Per Se

A mixed culture chemostat system was used to distinguish between the effects of carbohydrate availability per se and the low pH generated from carbohydrate metabolism on the proportions of bacteria within microbial communities. Nine oral bacteria were grown at pH 7 and pulsed with glucose on ten consecutive days. In one chemostat, the pH was maintained automatically at 7 throughout the experimental period, while in the other, pH control was discontinued for six hours after each pulse. Glucose pulses at neutral pH had little effect on the composition of the microflora. Only the proportions of A. viscosus and V. dispar increased; L. casei and S. mutans remained at low levels (0.2% and 1.0%, respectively). Acetate and propionate were the predominant end-products of metabolism; lactate levels were low. In contrast, when pH was allowed to fall after each glucose pulse, the composition of the microflora altered dramatically. The amounts of L. casei and S. mutans increased both as a proportion of the total count and in absolute numbers, as did V. dispar, whereas the amounts of the other Gram-negative organisms (B. intermedius, F. nucleatum, and N. subflava) and S. sanguis were considerably reduced. Lactate formed a major portion of the metabolic end-products. Successive glucose pulses resulted in both amplified changes in the microflora and a steadily greater rate and final extent of acid production. This is in agreement with the reported shifts in the oral microflora in vivo in response to frequent carbohydrate intake. Analysis of the data strongly suggests that the pH generated from carbohydrate metabolism, rather than carbohydrate availability per se, is responsible for the widely reported shifts in composition and metabolism of the oral microflora in vivo.

Cow red blood cells. I. Effect of purines, pyrimidines, and nucleosides in bovine red cell glycolysis

1979 ◽  
Vol 236 (5) ◽  
pp. C255-C261 ◽  
Author(s):  
M. J. Seider ◽  
H. D. Kim
Keyword(s):  
Pyruvate Kinase ◽  
Enzyme Activities ◽  
Blood Cells ◽  
Glycolytic Enzyme ◽  
Red Cells ◽  
The Other ◽  
Red Cell ◽  
Hexokinase Activity ◽  
Glycolytic Rate

Cow red cells, under in vitro incubation conditions, exhibit a comparatively low glycolytic rate of 0.56 +/- 0.05 micromol/(ml cells.h), with a ratio of lactate formed to glucose consumed of 1.58. It has been found that this low glycolytic rate can be stimulated 50--60% above the basal level in the presence of a variety of purine and pyrimidine compounds including adenosine, inosine, adenine, hypoxanthine, xanthine, and uracil. In contrast, calf red cells, which have a much higher glycolytic rate, display no discernible response to these agents. In attempts to elucidate the mechanism by which this stimulation takes place, both glucose transport and glycolytic enzyme activities were determined in the presence of these stimulators. Glucose influx in cow red cells, measured using the glucose analog 3-O-methyl-glucose, exhibits both a low Km of 117 microM and a Vmax of 0.38 micromol/(ml cells.min), and is unaltered in the presence of adenosine. On the other hand, hexokinase, which in normal hemolysates of cow red cells has an activity of 0.49 +/- 0.03 micromol/(g Hb.min). was found to be stimulated to 0.73 micromol/(g Hb.min) in the presence of adenine. Both pyruvate kinase and phosphofructokinase were unaffected by this compound. These data suggest that certain purines and pyrimidine compounds may exert their stimulatory effect on hexokinase activity, resulting in an augmentation of cow red cell glycolysis.

IN-VITRO SYNTHESIS OF ANDROGEN FROM PREGNENOLONE IN THE TESTES OF THE GOAT (CAPRA HIRCUS) AND IDENTIFICATION OF 5-PREGNENE-3β,17α,20α-TRIOL AS AN INTERMEDIATE IN THE METABOLIC PATHWAY OF PREGNENOLONE

1980 ◽  
Vol 84 (3) ◽  
pp. 381-390 ◽  
Author(s):  
MAKOTO MORI ◽  
SACHIKO MATSUKURA ◽  
KAZUHIKO KAWAKURA ◽  
BUN-ICHI TAMAOKI
Keyword(s):  
Time Course ◽  
Microsomal Fraction ◽  
Testicular Tissue ◽  
The Other ◽  
Capra Hircus ◽  
Cytosol Fraction ◽  
In Vitro Synthesis ◽  
Intermediary Metabolite ◽  
End Products

When [4–14C]pregnenolone was aerobically incubated in vitro in the presence of NAD+ and NADPH with cell-free homogenates of testicular tissue of adult domestic goats (Capra hircus), progesterone, 17α-hydroxypregnenolone, 17α-hydroxyprogesterone, 17α,20α-dihydroxy-4-pregnen-3-one, dehydroepiandrosterone, androstenedione and testosterone were identified as its known metabolites. Time-course studies on this metabolism showed that the production of 17α,20α-dihydroxy-4-pregnen-3-one and testosterone constantly increased up to the end of incubation, suggesting that these are both end-products of pregnenolone metabolism in this system. The other metabolites behaved as intermediates and were ultimately converted, in part, to testosterone by the testicular homogenates, indicating that testosterone was synthesized through both 4-ene and 5-ene-pathways. Furthermore, besides these metabolites, 5-pregnene-3β,17α,20α-triol was also identified as an intermediary metabolite, formed from pregnenolone through 17α-hydroxypregnenolone in the presence of NADPH, and further convertible into 17α,20α-dihydroxy-4-pregnen-3-one by the microsomal fraction and into 17α-hydroxypregnenolone by the cytosol fraction in the presence of NAD+ and NADP It was not, however, significantly transformed into C19-steroids. Furthermore, 17α,20α-dihydroxy-4-pregnen-3-one, which was formed either from 5-pregnene-3β,17α,20α-triol or from 17α-hydroxyprogesterone, remained almost unchanged without conversion to C19-steroids when incubated with the caprine testicular homogenates.

scholarly journals In Vitro Biosynthesis of Ether-Type Glycolipids in the Methanoarchaeon Methanothermobacter thermautotrophicus

2007 ◽  
Vol 189 (11) ◽  
pp. 4053-4061 ◽  
Author(s):  
Hiroyuki Morii ◽  
Tadashi Eguchi ◽  
Yosuke Koga
Keyword(s):  
Enzyme Activities ◽  
Cellular Localization ◽  
Glycerol Backbone ◽  
Sugar Moiety ◽  
Cell Extracts ◽  
Methanothermobacter Thermautotrophicus ◽  
In Vitro Biosynthesis ◽  
Low Activity ◽  
Lipid Substrate

ABSTRACT The biosynthesis of archaeal ether-type glycolipids was investigated in vitro using Methanothermobacter thermautotrophicus cell-free homogenates. The sole sugar moiety of glycolipids and phosphoglycolipids of the organism is the β-d-glucosyl-(1→6)-d-glucosyl (gentiobiosyl) unit. The enzyme activities of archaeol:UDP-glucose β-glucosyltransferase (monoglucosylarchaeol [MGA] synthase) and MGA:UDP-glucose β-1,6-glucosyltransferase (diglucosylarchaeol [DGA] synthase) were found in the methanoarchaeon. The synthesis of DGA is probably a two-step glucosylation: (i) archaeol + UDP-glucose → MGA + UDP, and (ii) MGA + UDP-glucose → DGA + UDP. Both enzymes required the addition of K+ ions and archaetidylinositol for their activities. DGA synthase was stimulated by 10 mM MgCl2, in contrast to MGA synthase, which did not require Mg2+. It was likely that the activities of MGA synthesis and DGA synthesis were carried out by different proteins because of the Mg2+ requirement and their cellular localization. MGA synthase and DGA synthase can be distinguished in cell extracts greatly enriched for each activity by demonstrating the differing Mg2+ requirements of each enzyme. MGA synthase preferred a lipid substrate with the sn-2,3 stereostructure of the glycerol backbone on which two saturated isoprenoid chains are bound at the sn-2 and sn-3 positions. A lipid substrate with unsaturated isoprenoid chains or sn-1,2-dialkylglycerol configuration exhibited low activity. Tetraether-type caldarchaetidylinositol was also actively glucosylated by the homogenates to form monoglucosyl caldarchaetidylinositol and a small amount of diglucosyl caldarchaetidylinositol. The addition of Mg2+ increased the formation of diglucosyl caldarchaetidylinositol. This suggested that the same enzyme set synthesized the sole sugar moiety of diether-type glycolipids and tetraether-type phosphoglycolipids.

scholarly journals Salicylate 5-Hydroxylase from Ralstonia sp. Strain U2: a Monooxygenase with Close Relationships to and Shared Electron Transport Proteins with Naphthalene Dioxygenase

2002 ◽  
Vol 184 (6) ◽  
pp. 1547-1555 ◽  
Author(s):  
Ning-Yi Zhou ◽  
Jumáa Al-Dulayymi ◽  
Mark S. Baird ◽  
Peter A. Williams
Keyword(s):  
Electron Transport ◽  
Sequence Similarity ◽  
Transport Proteins ◽  
Aromatic Rings ◽  
Naphthalene Dioxygenase ◽  
Cell Extracts ◽  
Transport Chain ◽  
Electron Transport Proteins

ABSTRACT The genes from the oxygenase cluster nagAaGHAbAcAd of naphthalene-degrading Ralstonia sp. strain U2 were cloned and overexpressed. Salicylate 5-hydroxylase (S5H) activity, converting salicylate to gentisate, was present in vitro only in the single extract of cells with overexpressed nagAaGHAb or in a mixture of three cell extracts containing, respectively, NagGH (the oxygenase components), NagAa (ferredoxin reductase), and NagAb (ferredoxin). Each of the three extracts required for S5H activity was rate limiting in the presence of excess of the others but, when in excess, did not affect the rate of catalysis. S5H catalyzed the 5-hydroxylation of the aromatic rings of 3- and 4-substituted salicylates. However, the methyl group of 5-methylsalicylate was hydroxylated to produce the 5-hydroxymethyl derivative and the 6-position on the ring of 5-chlorosalicylate was hydroxylated, producing 5-chloro-2,6-dihydroxybenzoate. In an assay for the nag naphthalene dioxygenase (NDO) based on the indole-linked oxidation of NADH, three extracts were essential for activity (NagAcAd, NagAa, and NagAb). NDO and S5H were assayed in the presence of all possible combinations of the nag proteins and the corresponding nah NDO proteins from the “classical” naphthalene degrader P. putida NCIMB9816. All three oxygenase components functioned with mixed combinations of the electron transport proteins from either strain. The S5H from strain U2 is a unique monooxygenase which shares sequence similarity with dioxygenases such as NDO but is also sufficiently similar in structure to interact with the same electron transport chain and probably does so in vivo during naphthalene catabolism in strain U2.

Enhancement of ADP-induced Platelet Aggregation by Adrenaline in Vivo and Its Prevention

1973 ◽  
Vol 29 (02) ◽  
pp. 490-498 ◽  
Author(s):  
Hiroh Yamazaki ◽  
Itsuro Kobayashi ◽  
Tadahiro Sano ◽  
Takio Shimamoto
Keyword(s):  
Platelet Count ◽  
Platelet Aggregation ◽  
Platelet Rich Plasma ◽  
The Other ◽  
Endothelial Surface ◽  
Important Interaction ◽  
Blood Coagulability ◽  
The Difference

SummaryThe authors previously reported a transient decrease in adhesive platelet count and an enhancement of blood coagulability after administration of a small amount of adrenaline (0.1-1 µg per Kg, i. v.) in man and rabbit. In such circumstances, the sensitivity of platelets to aggregation induced by ADP was studied by an optical density method. Five minutes after i. v. injection of 1 µg per Kg of adrenaline in 10 rabbits, intensity of platelet aggregation increased to 115.1 ± 4.9% (mean ± S. E.) by 10∼5 molar, 121.8 ± 7.8% by 3 × 10-6 molar and 129.4 ± 12.8% of the value before the injection by 10”6 molar ADP. The difference was statistically significant (P<0.01-0.05). The above change was not observed in each group of rabbits injected with saline, 1 µg per Kg of 1-noradrenaline or 0.1 and 10 µg per Kg of adrenaline. Also, it was prevented by oral administration of 10 mg per Kg of phenoxybenzamine or propranolol or aspirin or pyridinolcarbamate 3 hours before the challenge. On the other hand, the enhancement of ADP-induced platelet aggregation was not observed in vitro, when 10-5 or 3 × 10-6 molar and 129.4 ± 12.8% of the value before 10∼6 molar ADP was added to citrated platelet rich plasma (CPRP) of rabbit after incubation at 37°C for 30 second with 0.01, 0.1, 1, 10 or 100 µg per ml of adrenaline or noradrenaline. These results suggest an important interaction between endothelial surface and platelets in connection with the enhancement of ADP-induced platelet aggregation by adrenaline in vivo.

ALDOSTERONE STIMULATION IN VITRO

1965 ◽  
Vol 50 (2) ◽  
pp. 301-309 ◽  
Author(s):  
Jürg Müller
Keyword(s):  
Ammonium Chloride ◽  
Human Urine ◽  
Incubation Medium ◽  
The Other ◽  
Ammonium Ions ◽  
Response Curves ◽  
Urine Extract ◽  
Similar Dose ◽  
Aldosterone Production

ABSTRACT An extract of human urine, which was previously shown to stimulate aldosterone production by rat adrenal sections, was further purified. Evidence was obtained that its aldosterone-stimulating effect was due to the presence of ammonium ions. Addition of ammonium chloride and of urine extract to the incubation medium caused identical increases in aldosterone production in vitro. In addition to ammonium ions, rubidium and caesium ions also stimulated aldosterone production up to 250% that of control values without a significant effect on corticosterone production. Similar dose-response curves were obtained when increasing concentrations of potassium, ammonium, rubidium and caesium ions were tested. Aldosterone production was maximal at concentrations of 7 mval/1 and was significantly lower at higher concentrations. When ammonium chloride and ACTH were simultaneously added to the incubation medium, the production of aldosterone and of corticosterone was lower than with ACTH alone. On the other hand, the stimulating activity on aldosterone and corticosterone production by »TPN« (NADP) and glucose-6-phosphate was enhanced by the simultaneous addition of ammonium chloride.

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