scholarly journals The Remarkable Metabolism of Vickermania ingenoplastis: Genomic Predictions

Pathogens ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 68
Author(s):  
Fred R. Opperdoes ◽  
Anzhelika Butenko ◽  
Alexandra Zakharova ◽  
Evgeny S. Gerasimov ◽  
Sara L. Zimmer ◽  
...  
Keyword(s):  
Alternative Oxidase ◽  
Redox Balance ◽  
Cyclic Process ◽  
Gene Duplications ◽  
Anaerobic Conditions ◽  
Critical Difference ◽  
Unusual Structure ◽  
Unique Type ◽  
Malonyl Coa ◽  
Core Metabolism

A recently redescribed two-flagellar trypanosomatid Vickermania ingenoplastis is insensitive to the classical inhibitors of respiration and thrives under anaerobic conditions. Using genomic and transcriptomic data, we analyzed its genes of the core metabolism and documented that subunits of the mitochondrial respiratory complexes III and IV are ablated, while those of complexes I, II, and V are all present, along with an alternative oxidase. This explains the previously reported conversion of glucose to acetate and succinate by aerobic fermentation. Glycolytic pyruvate is metabolized to acetate and ethanol by pyruvate dismutation, whereby a unique type of alcohol dehydrogenase (shared only with Phytomonas spp.) processes an excess of reducing equivalents formed under anaerobic conditions, leading to the formation of ethanol. Succinate (formed to maintain the glycosomal redox balance) is converted to propionate by a cyclic process involving three enzymes of the mitochondrial methyl-malonyl-CoA pathway, via a cyclic process, which results in the formation of additional ATP. The unusual structure of the V. ingenoplastis genome and its similarity with that of Phytomonas spp. imply their relatedness or convergent evolution. Nevertheless, a critical difference between these two trypanosomatids is that the former has significantly increased its genome size by gene duplications, while the latter streamlined its genome.

scholarly journals Pyruvate Formate Lyase and Acetate Kinase Are Essential for Anaerobic Growth of Escherichia coli on Xylose

2004 ◽  
Vol 186 (22) ◽  
pp. 7593-7600 ◽  
Author(s):  
Adnan Hasona ◽  
Youngnyun Kim ◽  
F. G. Healy ◽  
L. O. Ingram ◽  
K. T. Shanmugam
Keyword(s):  
Escherichia Coli ◽  
Minimal Medium ◽  
High Capacity ◽  
Redox Balance ◽  
Anaerobic Growth ◽  
Acetate Kinase ◽  
Anaerobic Conditions ◽  
Pyruvate Formate Lyase ◽  
E Coli ◽  
Xylose Transport

ABSTRACT During anaerobic growth of bacteria, organic intermediates of metabolism, such as pyruvate or its derivatives, serve as electron acceptors to maintain the overall redox balance. Under these conditions, the ATP needed for cell growth is derived from substrate-level phosphorylation. In Escherichia coli, conversion of glucose to pyruvate yields 2 net ATPs, while metabolism of a pentose, such as xylose, to pyruvate only yields 0.67 net ATP per xylose due to the need for one (each) ATP for xylose transport and xylulose phosphorylation. During fermentative growth, E. coli produces equimolar amounts of acetate and ethanol from two pyruvates, and these reactions generate one additional ATP from two pyruvates (one hexose equivalent) while still maintaining the overall redox balance. Conversion of xylose to acetate and ethanol increases the net ATP yield from 0.67 to 1.5 per xylose. An E. coli pfl mutant lacking pyruvate formate lyase cannot convert pyruvate to acetyl coenzyme A, the required precursor for acetate and ethanol production, and could not produce this additional ATP. E. coli pfl mutants failed to grow under anaerobic conditions in xylose minimal medium without any negative effect on their survival or aerobic growth. An ackA mutant, lacking the ability to generate ATP from acetyl phosphate, also failed to grow in xylose minimal medium under anaerobic conditions, confirming the need for the ATP produced by acetate kinase for anaerobic growth on xylose. Since arabinose transport by AraE, the low-affinity, high-capacity, arabinose/H+ symport, conserves the ATP expended in pentose transport by the ABC transporter, both pfl and ackA mutants grew anaerobically with arabinose. AraE-based xylose transport, achieved after constitutively expressing araE, also supported the growth of the pfl mutant in xylose minimal medium. These results suggest that a net ATP yield of 0.67 per pentose is only enough to provide for maintenance energy but not enough to support growth of E. coli in minimal medium. Thus, pyruvate formate lyase and acetate kinase are essential for anaerobic growth of E. coli on xylose due to energetic constraints.

Uptake of Organic Substrates and Accumulation of Polyhydroxyalkanoates Linked with Glycolysis of Intracellular Carbohydrates under Anaerobic Conditions in the Biological Excess Phosphate Removal Processes

1992 ◽  
Vol 26 (5-6) ◽  
pp. 933-942 ◽  
Author(s):  
H. Satoh ◽  
T. Mino ◽  
T. Matsuo
Keyword(s):  
Reducing Power ◽  
Redox Balance ◽  
Phosphate Removal ◽  
Substrate Uptake ◽  
Organic Substrates ◽  
Mass Balances ◽  
Batch Experiments ◽  
Anaerobic Conditions ◽  
Removal Processes ◽  
Power And Energy

Anaerobic uptake mechanisms of acetate, propionate and lactate by the sludge developed in an anaerobic aerobic biological phosphate removal process was investigated. Anaerobic batch experiments were conducted with these substrates, and mass balances of materials involved in substrate uptake metabolism were calculated. These substrates were accumulated in the sludge as polyhydroxyalkanoates composed of 3-hydroxybutyrate, 3-hydroxyvalerate, 3-hydroxy-2-methylbutyrate and 3-hydroxy-2-methylvalerate. The reducing power necessary for the formation of polyhydroxyalkanoates from acetate and/or propionate was shown to be supplied from glycolysis of intracellular carbohydrates. Lactate was converted to 3-hydroxyvalerate rich polyhydroxyalkanoate via acetyl-CoA and propionyl-CoA by using propionate fermentation pathway. Redox balance was found to be a factor regulating the anaerobic uptake of substrates and their further metabolism. Glycogen seemed to serve not only as a source of reducing power necessary for the redox balance regulation but also as an important energy source, because glycolysis can provide both reducing power and energy. It was indicated that some bacteria might be able to get energy necessary for substrate uptake under strict anaerobic conditions not by the polyphosphate hydrolysis but by the consumption of intracellular carbohydrates.

Simultaneous Nitrogen and Phosphate Removal by the Intermittent Cyclic Process

1986 ◽  
Vol 18 (7-8) ◽  
pp. 319-326 ◽  
Author(s):  
N. Hayakawa ◽  
J. Tsuji ◽  
Y. Hamamoto
Keyword(s):  
Phosphate Removal ◽  
Cyclic Process ◽  
Intermittent Aeration ◽  
Anaerobic Conditions ◽  
Removal Rates ◽  
Batch Type ◽  
Treatment Processes ◽  
Plant Reactor ◽  
Nitrogen And Phosphate Removal ◽  
Aerobic And Anaerobic

By using the Intermittent Cyclic (IC) process which repeats aerobic and anaerobic conditions in an 18-m3 pilot plant reactor, domestic sewage was treated at a rate of 18 m3 per day. Operating condition was 4 cycles per day, intermittent aeration--4 hours, settling--1 hour, drawing--1 hour. Seven months of operation recorded high nitrogen removal rates: mean 86% and maximum 96%, phosphate removal rates: mean 83% and maximum 93%. Compared with conventional aerobic/anaerobic processes, the IC process, one of batch-type treatment processes, can advantageously and stably remove nitrogen and phosphate with repeated aeration and nonaeration under optimal control.

The Redfields meteorite—A unique iron from Western Australia

1973 ◽  
Vol 39 (301) ◽  
pp. 30-35 ◽  
Author(s):  
J. R. De Laeter ◽  
G. J. H. McCall ◽  
S. J. B. Reed
Keyword(s):  
Nickel Content ◽  
Iron Meteorite ◽  
Grain Structure ◽  
Iron Meteorites ◽  
High Carbon ◽  
Unusual Structure ◽  
Unique Type ◽  
Australian Museum ◽  
Graphite Inclusions ◽  
Western Australian

SummaryA metallic mass brought to the Western Australian Museum from the Wongan Hills district N.W. of Perth has been identified as an iron meteorite of unique type. It has graphite inclusions about I mm across distributed throughout the metal giving a ‘raisin bread’ appearance. Its nickel content (6·65 %) is comparable with that of coarse octahedrites but the kamacite grain structure is anomalous. Its gallium, germanium, and nickel contents place it close to, but outside, Wasson's chemical group IIb. Taenite is absent and troilite is rare. Neumann bands in the kamacite are distorted and the kamacite has flowed around large schreibersite inclusions. The latter have an exceptionally low nickel content (7·0 %) and probably formed at an unusually high temperature. The kamacite contains more phosphorus than normal iron meteorites, and small schreibersite grains in the kamacite are relatively nickel-poor (22 %). The unusual structure of this iron is thought to be due to one or more of the factors high carbon, high phosphorus, and relatively rapid cooling.

Fine Structure of Interdental Cells in the Mouse Cochlea

1970 ◽  
Vol 28 ◽  
pp. 140-141
Author(s):  
Roberta M. Bruck
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Young Adult ◽  
Uranyl Acetate ◽  
Ground Substance ◽  
Tectorial Membrane ◽  
Lead Citrate ◽  
Unusual Structure ◽  
Thin Sections ◽  
Collagenous Fibers

An unusual structure in the cochlea is the spiral limbus; this periosteal tissue consists of stellate fibroblasts and collagenous fibers embedded in a translucent ground substance. The collagenous fibers are arranged in vertical columns (the auditory teeth of Haschke). Between the auditory teeth are interdental furrows in which the interdental cells are situated. These epithelial cells supposedly secrete the tectorial membrane.The fine structure of interdental cells in the rat was reported by Iurato (1962). Since the mouse appears to be different, a description of the fine structure of mouse interdental cells' is presented. Young adult C57BL/6J mice were perfused intervascularly with 1% paraformaldehyde/ 1.25% glutaraldehyde in .1M phosphate buffer (pH7.2-7.4). Intact cochlea were decalcified in .1M EDTA by the method of Baird (1967), postosmicated, dehydrated, and embedded in Araldite. Thin sections stained with uranyl acetate and lead citrate were examined in a Phillips EM-200 electron microscope.

Paired helical filaments (PHF) in rats: An experimental animal model for Alzheimer's disease

1987 ◽  
Vol 45 ◽  
pp. 842-843
Author(s):  
V.J.A. Montpetit ◽  
S. Dancea ◽  
S.W. French ◽  
D.F. Clapin
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Animal Model ◽  
Paired Helical Filaments ◽  
Ethanol Intoxication ◽  
Drg Neurons ◽  
Critical Difference ◽  
Suitable Animal Model ◽  
The Central Nervous System ◽  
Chronic Ethanol Intoxication

A continuing problem in Alzheimer research is the lack of a suitable animal model for the disease. The absence of neurofibrillary tangles of paired helical filaments is the most critical difference in the processes by which the central nervous system ages in most species other than man. However, restricting consideration to single phenomena, one may identify animal models for specific aspects of Alzheimer's disease. Abnormal fibers resembling PHF have been observed in dorsal root ganglia (DRG) neurons of rats in a study of chronic ethanol intoxication and spontaneously in aged rats. We present in this report evidence that PHF-like filaments occur in ethanol-treated rats of young age. In control animals lesions similar in some respects to our observations of cytoskeletal pathology in pyridoxine induced neurotoxicity were observed.Male Wistar BR rats (Charles River Labs) weighing 350 to 400 g, were implanted with a single gastrostomy cannula and infused with a liquid diet containing 30% of total calories as fat plus ethanol or isocaloric dextrose.

Alternative oxidase from Arum and soybean: Its stabilization during purification

1996 ◽  
Vol 96 (4) ◽  
pp. 551-558 ◽  
Author(s):  
Qisen Zhang ◽  
Marcel H. N. Hoefnagel ◽  
Joseph T. Wiskich
Keyword(s):  
Alternative Oxidase

The Reaction of Thiol Compounds with the Vitamin-K Dependent Clotting Factors

1969 ◽  
Vol 21 (03) ◽  
pp. 573-579 ◽  
Author(s):  
P Fantl
Keyword(s):  
Prothrombin Time ◽  
Vitamin K ◽  
Anaerobic Conditions ◽  
Clotting Factors ◽  
Thiol Compounds ◽  
Aerobic Conditions ◽  
One Stage ◽  
Factor Ii ◽  
Ph Dependent ◽  
The One

SummaryTreatment of human and dog oxalated plasma with 0.2 to 1.0 × 10−1 M 2.3-dithiopropanol (BAL) or dithiothreitol (DTT) at 2–4° C for 30 min results in the reduction of the vitamin-K dependent clotting factors II, VII, IX and X to the respective-SH derivatives. The reaction is pH dependent. Under aerobic conditions the delayed one stage prothrombin time can be partly reversed. Under anaerobic conditions a gradual prolongation of the one stage prothrombin time occurs without reversal.In very diluted plasma treated with the dithiols, prothrombin can be converted into thrombin if serum as source of active factors VII and X is added. In contrast SH factors VII, IX and X are inactive in the specific tests. Reoxidation to active factors II, VII, IX and X takes place during adsorption and elution of the SH derivatives. The experiments have indicated that not only factor II but also factors VII, IX and X have active-S-S-centres.

METABOLISM OF 17α-HYDROXYPROGESTERONE-4-14C-17α-CAPROATE BY HOMOGENATES OF RAT LIVER AND HUMAN PLACENTA

1961 ◽  
Vol 36 (4) ◽  
pp. 511-519 ◽  
Author(s):  
Margaret Wiener ◽  
Charles I. Lupa ◽  
E. Jürgen Plotz
Keyword(s):  
Rat Liver ◽  
Human Placenta ◽  
Steric Hindrance ◽  
Placental Tissue ◽  
Caproic Acid ◽  
Major Product ◽  
Side Chain ◽  
Anaerobic Conditions ◽  
Prolonged Action ◽  
Long Acting

ABSTRACT 17α-hydroxyprogesterone-4-14C-17α-caproate (HPC), a long-acting progestational agent, was incubated with homogenates of rat liver and human placenta. The rat liver was found to reduce Ring A of HPC under anaerobic conditions to form allopregnane-3β,17α-diol-20-one-17α-caproate and pregnane-3β,17α-diol-20-one-17α-caproate, the allopregnane isomer being the major product. The caproic acid ester was neither removed nor altered during the incubation. Placental tissue did not attack HPC under conditions where the 20-ketone of progesterone was reduced. It is postulated that this absence of attack on the side chain is due to steric hindrance from the caproate ester, and that this may account for the prolonged action of HPC.

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