| susceptibility of anaerobic bacteria to metronidazole: relative resistance of non-spore-forming gram-positive baccilli. | susceptibility of 358 clinical isolates of obligate anaerobes to metronidazole was determined by an agar-dilution technique. only 66% of all isolates were inhibited by 6.25 mug/ml, whereas 30% required larger than or equal to 50 mug/ml. considerable variation in susceptibility was observed among different genera and species of bacteria. fusobacterium was most senstitive, followed by clostridium, bacteroides and peptococcus, peptostreptococcus, veillonella and acidaminococcus, and non-spore-formi ... | 1975 | 163867 |
| ticarcillin disodium in anaerobic infections. | twenty-five patients were treated with ticarcillin disodium, 18 of whom had anaerobic infections that included pleuropulmonary infections (seven), mandibular osteomyelitis (four), perirectal abscess (two), sepsis, primary site unknown (one), liver abscess (one), pelvic abscess (one), decubitus ulcer (one), and synergistic gangrene (one). seven had no anaerobic infections. three had anaerobic septicemia. culture results included anaerobes: peptococci (ten), peptostreptococci (ten), bacteroides fr ... | 1978 | 718311 |
| cloning and sequencing of the genes of 2-hydoxyglutaryl-coa dehydratase from acidaminococcus fermentans. | two genomic libraries from acidaminococcus fermentans dna constructed with the lambda vectors gt11 and embl 3 were screened with antisera raised against 2-hydroxyglutaryl-coa dehydratase. two clones giving the strongest reaction in the immunoassay were analyzed further, one was a lambda gt11 clone with an insert of 2050 bp and one was a lambda embl-3 clone with an insert of approximately 11,000 bp. escherichia coli cells infected with the lambda gt11 clone expressed the alpha subunit of the dehy ... | 1989 | 2659350 |
| colony counts and characterization of bacteria adherent to the rumen wall and desquamated epithelial cells in conventional young lambs. | characterization and enumeration of the adherent epimural community of the rumen wall of young, conventionally reared lambs were carried out from 2 to 21 days after birth. three hundred strains were isolated by anaerobic procedures from three sites: dorsal, ventral, and caudal sacs, and from the sloughed epithelial cells. the population of epimural bacteria was very dense from the first days of the lamb's life. this population increased slightly with age. during the first week the counts were si ... | 1989 | 2766120 |
| a sodium ion gradient as energy source for peptostreptococcus asaccharolyticus. | the determination of enzymatic activities in cell-free extracts of acidaminococcus fermentans and peptostreptococcus asaccharolyticus led to a refined scheme for the pathway of glutamate fermentation via (r)-2-hydroxyglutarate to acetate and butyrate. from the ratio of these products the amount of atp generated by substrate level phosphorylation was calculated. growth experiments with the organisms including clostridium symbiosum and clostridium tetanomorphum indicated that a sodium gradient con ... | 1985 | 4037980 |
| isolation of acidaminococcus fermentans and megasphaera elsdenii from normal human feces. | fecal bacterial cultures from 40 normal humans yielded megasphaera elsdenii from four individuals and acidaminococcus fermentans from 10 individuals, with two individuals having both organisms. | 1974 | 4589136 |
| anaerobic infections in childhood. | anaerobic bacteria are part of the normal flora of mucous membranes and outnumber aerobic bacteria in the oral cavity and gastrointestinal tract. anaerobes can be isolated from pediatric patients with various infections when appropriate techniques for transportation and cultivation of samples are employed. frequently anaerobes are isolated in combination with other facultative or aerobic bacteria. the genera or groups of anaerobes most frequently isolated from pyogenic infections in children are ... | 1984 | 6372028 |
| purification of 2-hydroxyglutaryl-coa dehydratase from acidaminococcus fermentans. an iron-sulfur protein. | 1. the (r)-2-hydroxyglutaryl-coa dehydratase system from acidaminococcus fermentans was separated by chromatography of cell-free extracts on q-sepharose into two components, an activator and the actual dehydratase. the latter enzyme was further purified to homogeneity by chromatography on blue-sepharose. it is an iron-sulfur protein (mr 210,000) consisting of two different polypeptides (alpha, mr 55,000, and beta, mr 42,000) in an alpha 2 beta 2 structure with probably two [4fe-4s] centers. afte ... | 1987 | 3691501 |
| ischaemic mouse thigh model for evaluation of pathogenicity of non-clostridial anaerobes. | a mouse thigh model has been devised in which the growing culture of non-clostridial anaerobe in the ischaemic tissue produces inflammatory swelling and death. the swelling of the right thigh served as an index of pathogenicity of the test strain in comparison to the negatively reacting left thigh which received injection of the control strain of bifidobacterium infantis. actinomyces naeslundii exceptionally caused death in all animals within 24 h. mortality and thigh swelling were pronounced (g ... | 1989 | 2914729 |
| equilibrium constants of several reactions involved in the fermentation of glutamate. | the equilibrium constants of the reactions catalysed by (s)-citramalate lyase and (r)-2-hydroxyglutarate dehydrogenase were determined using the purified enzymes from clostridium tetanomorphum and acidaminococcus fermentans, respectively. the former constant had to be determined at high ionic strength (i). therefore it was corrected to i = 0.1 m by applying single-ion activity coefficients estimated from literature data. the result (kapp = 4.31 +/- 0.07 m-1; direction of citramalate formation) a ... | 1987 | 2883006 |
| the sodium cycle: a novel type of bacterial energetics. | the progress of bioenergetic studies on the role of na+ in bacteria is reviewed. experiments performed over the past decade on several bacterial species of quite different taxonomic positions show that na+ can, under certain conditions, substitute for h+ as the coupling ion. various primary na+ pumps (delta mu na+ generators) are described, i.e., na+ -motive decarboxylases, nadh-quinone reductase, terminal oxidase, and atpase. the delta mu na+ formed is shown to be consumed by na+ driven atp-syn ... | 1989 | 2687258 |
| substrate stereochemistry of the biotin-dependent sodium pump glutaconyl-coa decarboxylase from acidaminococcus fermentans. | the steric course of the decarboxylation of glutaconyl-coa to crotonyl-coa, catalysed by the biotin-dependent sodium pump glutaconyl-coa decarboxylase from acidaminococcus fermentans, was elucidated using the sequence: chiral acetate----citrate----glutamate----glutaconyl-coa----crotonyl-coa ----chiral acetate. since glutaconyl-coa or glutaconate labeled at c-4 was subjected to rapid chemical or enzymatic exchanges, glutamate was fermented to acetate by growing cells of a. fermentans. the analysi ... | 1986 | 2422028 |
| the sodium pump glutaconyl-coa decarboxylase from acidaminococcus fermentans. specific cleavage by n-alkanols. | glutaconyl-coa decarboxylase from acidaminococcus fermentans was inactivated by incubation with n-alkanols at 37 degrees c. the concentration of the alcohol required for complete inactivation decreased with increasing chain length; e.g. 2 m ethanol was as potent as 2 mm hexanol or 0.5 mm decanol. the data indicate a binding of the alcohol to the enzyme with an energy of about 4 kj/methylene group. sodium ions prevented the inactivation (50% at 30 mm nacl). k+, nh4+, cs+ and mg2+ had no influence ... | 1986 | 2422027 |
| rapid diagnosis of anaerobic gram-positive cocci by salt tolerance. | the maximum salt tolerance was 2.5% in cases of peptostreptococcus anaerobius and peptococcus prevotii, 3% in ruminococcus albus, 4% in acidaminococcus fermentans, peptococcus niger and megasphaera elsdenii and 5% in peptococcus magnus. the biochemical tests being largely inactive and time consuming the findings of salt tolerance if combined with those of morphological data provide clue to the rapid identification of gram-positive anaerobic cocci. | 1994 | 7963612 |
| obligately anaerobic bacterial species isolated from foot-rot lesions in goats. | lesions showing clinical signs of foot-rot from 120 goats were cultured on six selective media during october 1987 to november 1988. a total of 582 strictly anaerobic microorganisms belonging to 50 different species was isolated and identified. the anaerobes most frequently isolated belonged to the following genera: bacteroides (80%), peptostreptococcus (63.6%), megasphaera (40%), fusobacterium (29.2%), clostridium (22.5%), propionibacterium (12.5%), eubacterium (11.7%) and leptotrichia (10.8%). ... | 1990 | 2271912 |
| carbon-13 labelled biotin--a new probe for the study of enzyme catalyzed carboxylation and decarboxylation reactions. | [2'-13c]biotin was incorporated into avidin (egg white), glutaconyl-coa decarboxylase (ec 4.1.1.70) from acidaminococcus fermentans and the biotin carrier of transcarboxylase from propionibacterium freudenreichii (ec 2.1.3.1). 13c-nmr measurements showed an upfield shift of the carbonyl carbon of 3.1 and 2.0 ppm for both enzymes, whereas binding to avidin induced no significant change of the chemical shift as compared to free biotin. the data indicate that the enzymes provide an electronic envir ... | 1990 | 2269346 |
| the biotin-dependent sodium ion pump glutaconyl-coa decarboxylase from fusobacterium nucleatum (subsp. nucleatum). comparison with the glutaconyl-coa decarboxylases from gram-positive bacteria. | membrane preparations of fusobacterium nucleatum grown on glutamate contain glutaconyl-coa decarboxylase at a high specific activity (13.8 nkat/mg protein). the enzyme was solubilized with 2% triton x-100 in 0.5 m nacl and purified 63-fold to a specific activity of 870 nkat/mg by affinity chromatography on monomeric avidin-sepharose. the activity of the decarboxylase was strictly dependent on na+ (km = 3 mm) and was stimulated up to 3-fold by phospholipids. the glutaconyl-coa decarboxylases from ... | 1990 | 2244788 |
| isolation and identification of anaerobic bacteria from ovine foot rot in spain. | a microbiological study was made of 125 merino sheep showing clinical signs of foot rot. a total of 435 strictly anaerobic strains were isolated, belonging to the following genera: bacteroides, peptostreptococcus, tissierella, fusobacterium, megasphaera, eubacterium, acidaminococcus, clostridium, peptococcus and propionibacterium. of the 35 species obtained, the following were found in more than 10 per cent of animals sampled: bacteroides nodosus, b putredinis, b buccae, b ruminicola subspecies ... | 1990 | 2236925 |
| synthesis and properties of (r)-2-hydroxyglutaryl-1-coa. (r)-2-hydroxyglutaryl-5-coa, an erroneous product of glutaconate coa-transferase. | 1) (r)-2-hydroxyglutaryl-1-coa was synthesised starting from (r)-5-oxotetrahydrofuran-2-carboxylic acid (gamma-lactone of (r)-2-hydroxyglutarate) which was converted to the acylchloride and condensed with n-capryloylcysteamine. the lactone ring of the resulting thiolester was opened by acid hydrolysis and the coa derivative was obtained by transesterification. 2) pure glutaconate coa-transferase from acidaminococcus fermentans catalysed the formation of the 1- and the 5-isomer of (r)-2-hydroxygl ... | 1991 | 1872995 |
| fermentation of trans-aconitate via citrate, oxaloacetate, and pyruvate by acidaminococcus fermentans. | growing cells of acidaminococcus fermentans (dsm 20731 and atcc 25085) fermented trans-aconitate via citrate, oxaloacetate, and pyruvate to approximately 2 co2, 1.8 acetate, 0.1 butyrate and 0.9 h2. the carbon and electron recoveries were close to 100%. on citrate no growth was observed and washed cells were unable to ferment this tricarboxylate. in cell-free extracts, however, citrate as well as trans-aconitate were readily fermented to co2 and acetate. under these conditions, also cis-aconitat ... | 1996 | 8929281 |
| sodium ion-dependent hydrogen production in acidaminococcus fermentans. | acidaminococcus fermentans is able to ferment glutamate to ammonia, co2, acetate, butyrate, and h2. the molecular hydrogen (approximately 10 kpa; e' = -385 mv) stems from nadh generated in the 3-hydroxybutyryl-coa dehydrogenase reaction (e degrees ' = -240 mv) of the hydroxyglutarate pathway. in contrast to growing cells, which require at least 5 mm na+, a na+-dependence of the h2-formation was observed with washed cells. whereas the optimal glutamate fermentation rate was achieved already at 1 ... | 1996 | 8929282 |
| susceptibilities of anaerobic bacteria isolated from animals with ovine foot rot to 28 antimicrobial agents. | the agar dilution method was used to determine the inhibitory activities of 28 antimicrobial agents against 35 strains of the genus peptostreptococcus, 4 strains of the species peptococcus niger, 20 strains of the species megasphaera elsdenii, 7 strains from the species acidaminococcus fermentans, 8 strains of the genus clostridium, 11 strains of the genus eubacterium, and 1 strain of the species propionibacterium acidipropionici, all of which were isolated from 125 clinical cases of ovine foot ... | 1992 | 1590689 |
| 2-hydroxyglutaryl-coa dehydratase from fusobacterium nucleatum (subsp. nucleatum): an iron-sulfur flavoprotein. | anaerobically prepared cell-free extracts from fusobacterium nucleatum contain 2-hydroxyglutaryl-coa dehydratase with a specific activity of 20 nkat mg-1. the enzyme was purified 24-fold to a specific activity of 480 nkat mg-1 by anion exchange chromatography, gel filtration and chromatography on blue-sepharose. the activity of the purified enzyme was strictly dependent on the reductant ti(iii)citrate and stimulated 25-fold by 0.15 mm atp and 5 mm mgcl2. atp is hydrolysed to adp during incubatio ... | 1992 | 1417419 |
| phylogenetic and chemotaxonomic characterization of acidaminococcus fermentans. | the phylogenetic position of acidaminococcus fermentans was determined by comparative sequence analysis of the 16s rrna. this gram-negative bacterium is a member of the sporomusa cluster that is defined by other gram-negative bacteria, i.e. sporomusa, megasphaera, selenomonas, butyrivibrio, pectinatus, and zymophilus. the branching point of this group within the radiation of gram-positive bacteria of the clostridium/bacillus subphylum and adjacent to peptococcus niger could be confirmed. chemota ... | 1992 | 1385264 |
| rapid screening of veillonella by ultraviolet fluorescence. | among 51 strains of anaerobic gram-negative cocci belonging to the family veillonellaceae, all strains of veillonella (v. parvula and v. alcalescens) displayed red fluorescence under long-wave (366 nm) ultraviolet light, whereas no acidaminococcus or megasphaera demonstrated fluorescence. in contrast to bacteroides melaninogenicus, growth of veillonella does not require hemin and menadione, and flourescence is rapidly lost upon exposure to air. the fluorescent component of a strain of v. parvula ... | 1975 | 1419 |
| succiniclasticum ruminis gen. nov., sp. nov., a ruminal bacterium converting succinate to propionate as the sole energy-yielding mechanism. | a gram-negative, anaerobic, nonmotile, non-spore-forming, rod-shaped bacterium that fermented succinate quantitatively to propionate was isolated from a high dilution of rumen ingesta obtained from a dairy cow fed a production diet containing grass silage as the main roughage source. this organism did not grow on any of the following energy sources: 12 carbohydrates, pyruvate, lactate, 7 dicarboxylic acids, aspartate, citrate, and trans-aconitate. both rumen fluid and yeast extract were necessar ... | 1995 | 7537062 |
| the reversible dehydration of (r)-2-hydroxyglutarate to (e)-glutaconate. | 1. during fermentation with whole cells of acidaminococcus fermentans or clostridium microsporum the pro-3s hydrogen of (r)-2-hydroxyglutarate or of its precursor (s)-glutamate is eliminated stereospecifically. since (e)-glutaconate but not its z isomer is fermented by whole cells or cell-free extracts of a. fermentans, the overall dehydration of (r)-2-hydroxyglutarate to (e)-glutaconate can be described as syn. 2. the fermentation of (e)-glutaconate required acetyl phophate, coa and nad, that o ... | 1980 | 7398622 |
| glutaconate coa-transferase from acidaminococcus fermentans. | 1. glutaconate coa-transferase catalyses the transfer of coas- from acetyl-coa preferentially to (e)-glutaconate, but glutarate, (r)-2-hydroxyglutarate, acrylate and propionate are also good acceptors. no reaction was observed with (z)-glutaconate and c4-dicarboxylic acids. 2. the product of the reaction of acetyl-coa with (e)-glutaconate is the 1-isomer of glutaconyl-coa, i.e. the thiol ester is conjugated with the double bond. other results indicate, however, that with (r)-2-hydroxyglutarate a ... | 1981 | 6945182 |
| purification, characterisation and reconstitution of glutaconyl-coa decarboxylase, a biotin-dependent sodium pump from anaerobic bacteria. | glutaconyl-coa decarboxylase from acidaminococcus fermentans is a biotin enzyme, which is integrated into membranes. it is activated by triton x-100 and inhibited by avidin. the results obtained by a combination of both agents indicate that biotin and the substrate-binding site are located on the same side of the membrane. the decarboxylase was solubilized with triton x-100 and purified by affinity chromatography on monomeric avidin-sepharose. the enzyme is composed of three types of polypeptide ... | 1983 | 6628393 |
| culture-dependent and culture-independent characterization of microbial assemblages associated with high-temperature petroleum reservoirs. | recent investigations of oil reservoirs in a variety of locales have indicated that these habitats may harbor active thermophilic prokaryotic assemblages. in this study, we used both molecular and culture-based methods to characterize prokaryotic consortia associated with high-temperature, sulfur-rich oil reservoirs in california. enrichment cultures designed for anaerobic thermophiles, both autotrophic and heterotrophic, were successful at temperatures ranging from 60 to 90 degrees c. heterotro ... | 2000 | 10653739 |
| the involvement of coenzyme a esters in the dehydration of (r)-phenyllactate to (e)-cinnamate by clostridium sporogenes. | phenyllactate dehydratase from clostridium sporogenes grown anaerobically on l-phenylalanine catalyses the reversible syn-dehydration of (r)-phenyllactate to (e)-cinnamate. purification yielded a heterotrimeric enzyme complex (130 +/- 15 kda) composed of flda (46 kda), fldb (43 kda) and fldc (40 kda). by re-chromatography on q-sepharose, the major part of flda could be separated and identified as oxygen insensitive cinnamoyl-coa:phenyllactate coa-transferase, whereas the transferase depleted tri ... | 2000 | 10849007 |
| [cefotiam passage into the maxillary sinus tissues]. | clinical study was made on cefotiam (ctm) and the following results were obtained. tissue concentrations of ctm were determined 1 hour after intravenous injection (ctm 1 g) in chronic sinusitis and maxillary cyst. concentrations of ctm were 16.53 micrograms/g, 13.26 micrograms/g in mucosa of the maxillary sinus, maxillary cyst, respectively. antibacterial activity of ctm was measured on escherichia coli, staphylococcus epidermidis, aerococcus, acidaminococcus fermentans, peptostreptococcus anaer ... | 1983 | 6325743 |
| catabolism of diadenosine 5',5"'-p1,p4-tetraphosphate in procaryotes. purification and properties of diadenosine 5',5"'-p1,p4-tetraphosphate (symmetrical) pyrophosphohydrolase from escherichia coli k12. | enzymatic activity which hydrolyzes diadenosine 5',5"'-p1,p4-tetraphosphate (ap4a) yielding adp has been identified in extracts of eubacteria, escherichia coli and acidaminococcus fermentans, and of a highly thermophilic archaebacterium, pyrodictum occultum. specific ap4a (symmetric) pyrophosphohydrolase from escherichia coli k12 has been purified almost 400-fold. the preparation was free of phosphatase, atpase, phosphodiesterase, amp-nucleosidase, and adenylate kinase. the ap4a pyrophosphohydro ... | 1983 | 6317672 |
| a biotin-dependent sodium pump: glutaconyl-coa decarboxylase from acidaminococcus fermentans. | the decarboxylation of glutaconyl-coa to crotonyl-coa in the anaerobic bacterium acidaminococcus fermentans is catalysed by a membrane-bound, biotin-dependent enzyme which requires na+ for activity. inverted vesicles from a. fermentans accumulated na+ only if glutaconyl-coa was decarboxylated. the na+ uptake was inhibited by avidin but not by the avidin biotin complex. detergents and ionophores such as monensin also prevented the na+ transport. the results indicate that the enzyme is able to con ... | 1982 | 6293874 |
| acidaminococcus gen. n., acidaminococcus fermentans sp. n., anaerobic gram-negative diplococci using amino acids as the sole energy source for growth. | acidaminococcus gen. n. and the type species acidaminococcus fermentans sp. n. were described. amino acids, of which glutamic acid is the most important, could serve as the sole energy source for growth. acetic and butyric acids and co(2) were produced; propionic acid and hydrogen were not produced. amino acid media supporting growth and the amino acid and vitamin requirements were described. glucose was frequently not fermented or was weakly catabolized. derivative products from glucose autocla ... | 1969 | 5784223 |
| two pathways of glutamate fermentation by anaerobic bacteria. | two pathways are involved in the fermentation of glutamate to acetate, butyrate, carbon dioxide, and ammonia-the methylaspartate and the hydroxyglutarate pathways which are used by clostridium tetanomorphum and peptococcus aerogenes, respectively. although these pathways give rise to the same products, they are easily distinguished by different labeling patterns of the butyrate when [4-(14)c]glutamate is used as substrate. schmidt degradation of the radioactive butyrate from c. tetanomorphum yie ... | 1974 | 4813895 |
| sodium ion-translocating decarboxylases. | the review is concerned with three na(+)-dependent biotin-containing decarboxylases, which catalyse the substitution of co(2) by h(+) with retention of configuration (deltag degrees '=-30 kj/mol): oxaloacetate decarboxylase from enterobacteria, methylmalonyl-coa decarboxylase from veillonella parvula and propiogenium modestum, and glutaconyl-coa decarboxylase from acidaminococcus fermentans. the enzymes represent complexes of four functional domains or subunits, a carboxytransferase, a mobile al ... | 2001 | 11248185 |
| phylogenetic placement of dialister pneumosintes (formerly bacteroides pneumosintes) within the sporomusa subbranch of the clostridium subphylum of the gram-positive bacteria. | the nucleotide sequence of the 16s rrna gene of the type strain of dialister pneumosintes was determined. phylogenetic analysis revealed that this species belongs to the sporomusa branch of the clostridium subphylum of the gram-positive bacteria and should therefore be excluded from the family bacteroidaceae. within this branch, which encompasses several other gram-negative taxa, such as acidaminococcus, pectinatus, phascolarcobacterium, quinella, selenomonas, and zymophilus, dialister showed a ... | 1995 | 7537075 |
| molecular characterization of phenyllactate dehydratase and its initiator from clostridium sporogenes. | the heterotrimeric phenyllactate dehydratase from clostridium sporogenes, fldabc, catalyses the reversible dehydration of (r)-phenyllactate to (e)-cinnamate in two steps: (i) coa-transfer from the cofactor cinnamoyl-coa to phenyllactate to yield phenyllactyl-coa and the product cinnamate mediated by flda, a (r)-phenyllactate coa-transferase; followed by (ii) dehydration of phenyllactyl-coa to cinnamoyl-coa mediated by heterodimeric fldbc, a phenyllactyl-coa dehydratase. phenyllactate dehydratase ... | 2002 | 11967068 |
| activation of (r)-2-hydroxyglutaryl-coa dehydratase from acidaminococcus fermentans. | (r)-2-hydroxyglutaryl-coa dehydratase (hgdab) from acidaminococcus fermentans catalyses the reversible dehydration of its substrate to glutaconyl-coa. the enzyme has to be activated by atp, mgcl2, and ti(iii)citrate by an activator protein (hgdc) that is present in the organism at very low concentrations. cell-free extracts of a recombinant escherichia coli strain, in which hgdc was expressed, contained the activator with a specific activity of up to 45 u'/mg protein (1 u' is the amount of activ ... | 1995 | 7607244 |
| identification of glutamate beta 54 as the covalent-catalytic residue in the active site of glutaconate coa-transferase from acidaminococcus fermentans. | in the course of glutamate fermentation by acidaminococcus fermentans glutaconate coenzyme a-transferase catalyzes the transfer of coas- from acetyl-coa to (r)-2-hydroxyglutarate, forming (r)-2-hydroxyglutaryl-coa. glutamate (e) 54 of the beta-subunit was postulated to be directly involved in catalysis by formation of a coash ester intermediate [(1994) eur. j. biochem., in press]. in order to prove this preliminary result, the following mutations, beta e54a, beta e64a, beta e54q and beta e54d, w ... | 1995 | 7805881 |
| posex: vectors for osmotically controlled and finely tuned gene expression in escherichia coli. | expression of the prou operon of escherichia coli is directly proportional to the osmolarity of the growth medium. the basal level of prou transcription is very low, but a large increase is triggered by a sudden rise in the external osmolarity. this increased expression is maintained for as long as the osmotic stimulus persists. we have capitalized upon these regulatory features of the prou operon and have constructed a series of expression vectors (posex) permitting osmotically controlled expre ... | 1994 | 7828862 |
| location of the two genes encoding glutaconate coenzyme a-transferase at the beginning of the hydroxyglutarate operon in acidaminococcus fermentans. | glutaconate coenzyme a-transferase (gct) from acidaminococcus fermentans consists of two subunits (gcta, 35725 da and gctb, 29168 da). the n-termini sequences of both subunits were determined. dna sequencing of a subgenomic fragment of a. fermentans revealed that the genes encoding glutaconate coa-transferase (gctab) are located upstream of a gene cluster formed by gcda, hgdc, hgda and hgdb in this order. further upstream of gcta, a dna sequence was detected showing significant similarities to s ... | 1994 | 7957258 |
| emendation of the description of acidaminococcus fermentans, a trans-aconitate- and citrate-oxidizing bacterium. | ruminal fluid which was enriched with trans-aconitate yielded a gram-negative diplococcus (strain ao) which was identified by 16s ribosomal dna sequence analysis as acidaminococcus fermentans. in contrast to the original description, the a. fermentans type strain and strain ao were found to utilize citrate as an energy source and to produce hydrogen and hydrogen sulfide. the descriptions of the genus and species are emended accordingly. | 1994 | 8068544 |
| ability of acidaminococcus fermentans to oxidize trans-aconitate and decrease the accumulation of tricarballylate, a toxic end product of ruminal fermentation. | mixed ruminal bacteria convert trans-aconitate to tricarballylate, a tricarboxylic acid which chelates blood divalent cations and decreases their availability (j. b. russell and p. j. van soest, appl. environ. microbiol. 47:155-159, 1984). decreases in blood magnesium in turn cause a potentially fatal disease known as grass tetany. trans-aconitate was stoichiometrically reduced to tricarballylate by selenomonas ruminantium, a common ruminal bacterium in grass-fed ruminants (j. b. russell, appl. ... | 1994 | 8074529 |
| identification of the gene encoding the activator of (r)-2-hydroxyglutaryl-coa dehydratase from acidaminococcus fermentans by gene expression in escherichia coli. | (r)-2-hydroxyglutaryl-coa dehydratase (hgda/b) from acidaminococcus fermentans requires an activator protein for activity. this activator (hgdc) has not yet been purified from its natural source due to its low concentration combined with an extreme sensitivity towards oxygen. gene expression in escherichia coli identified an open reading frame (780 bp) as the gene encoding hgdc. dehydratase activity was stimulated at least tenfold by cell-free extracts of e. coli cells transformed with a plasmid ... | 1993 | 8365476 |
| cloning, sequencing and expression of the gene encoding the carboxytransferase subunit of the biotin-dependent na+ pump glutaconyl-coa decarboxylase from acidaminococcus fermentans in escherichia coli. | 1. the primary sodium-ion pump glutaconyl-coa decarboxylase (gcd) from acidaminococcus fermentans is composed of four subunits: gcda, the carboxytransferase (65 kda), gcdb, the carboxylyase (36 kda), gcdc, the biotin carrier (24 kda) and gcdd (14 kda) of unknown function. a genomic library of a. fermentans was screened with an antiserum raised against whole gcd. a clone giving the strongest reaction in an immunoassay contained a 12-kbp genomic fragment from a. fermentans and was analysed further ... | 1993 | 8382157 |
| non-sporing anaerobes in certain surgical group of patients. | the magnitude of non-sparing anaerobic (nsa) infections has been defined in the postoperative wounds on colorectum in children (57.1%), general surgery (0%), abdominoperineal and uterocervical operations (11-45%) in gynaecologic and obstetrical cases and perforative peritonitis (25.8-32.3%). children below the 6 months age group bear less risk of acquiring nsa infection. under certain situations, metronidazole combats nsa infections in a better way than other antibacterials. the bacteriology of ... | 1995 | 8648152 |
| structural basis for stereo-specific catalysis in nad(+)-dependent (r)-2-hydroxyglutarate dehydrogenase from acidaminococcus fermentans. | nad(+)-dependent (r)-2-hydroxyglutarate dehydrogenase (hgdh) catalyses the reduction of 2-oxoglutarate to (r)-2-hydroxyglutarate and belongs to the d-2-hydroxyacid nad(+)-dependent dehydrogenase (d-2-hydroxyacid dehydrogenase) protein family. its crystal structure was determined by phase combination to 1.98 a resolution. structure-function relationships obtained by the comparison of hgdh with other members of the d-2-hydroxyacid dehydrogenase family give a chemically satisfying view of the subst ... | 2005 | 15634349 |
| re-face stereospecificity at c4 of nad(p) for alcohol dehydrogenase from methanogenium organophilum and for (r)-2-hydroxyglutarate dehydrogenase from acidaminococcus fermentans as determined by 1h-nmr spectroscopy. | the two diastereotopic protons at c4 of nad(p)h are seen separately in 1h-nmr spectra. this fact was used to determine the stereospecificity at c4 of nad(p) for the nadp-dependent alcohol dehydrogenase from methanogenium organophilum and for the nad-dependent (r)-2-hydroxyglutarate dehydrogenase from acidaminococcus fermentans. the reduction of nadp+ with [2h6]ethanol was found to yield (4r)-[4-2h1]nadph and the oxidation of (4r)-[4-2h1]nadh with 2-oxoglutarate to yield unlabelled [4-1h]nad+. th ... | 1996 | 8980127 |
| oxygen exchange between acetate and the catalytic glutamate residue in glutaconate coa-transferase from acidaminococcus fermentans. implications for the mechanism of coa-ester hydrolysis. | the exchange of oxygen atoms between acetate, glutaryl-coa, and the catalytic glutamate residue in glutaconate coa-transferase from acidaminococcus fermentans was analyzed using [(18)o(2)]acetate together with matrix-assisted laser desorption/ionization time of flight mass spectrometry of an appropriate undecapeptide. the exchange reaction was shown to be site-specific, reversible, and required both glutaryl-coa and [(18)o(2)]acetate. the observed exchange is in agreement with the formation of a ... | 1999 | 10409616 |
| succinispira mobilis gen. nov., sp. nov., a succinate-decarboxylating anaerobic bacterium. | a succinate-decarboxylating anaerobic bacterium, designated strain 19gly1t, was previously isolated from a mixed culture growing with glycolate. the almost complete sequence of the 16s rrna gene (1495 nt) was determined for this strain. on the basis of 16s rrna gene sequence homology, strain 19gly1t was identified as a member of the sporomusa sub-branch of the 'low g+c' gram-positive bacteria. phylogenetic analysis showed that strain 19gly1t was most closely related to succiniclasticum ruminis, ... | 1999 | 10425757 |
| 2-hydroxyglutaryl-coa dehydratase from clostridium symbiosum. | component d (hgdab) of 2-hydroxyglutaryl-coa dehydratase from clostridium symbiosum was purified to homogeneity. it is able to use component a from acidaminococcus fermentans (hgdc) to initiate catalysis together with atp, mg2+ and a strong reducing agent such as ti(iii)citrate. component d from c. symbiosum has a 6 x higher specific activity compared with that from a. fermentans and contains a second [4fe-4s] cluster but the same amount of riboflavin 5'-phosphate (1.0 per heterodimeric enzyme, ... | 1999 | 10491198 |
| comparative in vitro activities of ertapenem (mk-0826) against 1,001 anaerobes isolated from human intra-abdominal infections. | by using an agar dilution method, the comparative in vitro activities of ertapenem (mk-0826) were studied against 1,001 anaerobes isolated from human intra-abdominal infections in 17 countries worldwide. mk-0826 was uniformly active against all isolates, including all bacteroides fragilis group species isolates, with the exception of 12 of 61 (20%) strains of bilophila wadsworthia, 3 strains of lactobacilli, and 1 isolate of acidaminococcus fermentans. geographical variation in activity was not ... | 2000 | 10952584 |
| succinyl-coa:3-ketoacid coa transferase (scot): cloning of the human scot gene, tertiary structural modeling of the human scot monomer, and characterization of three pathogenic mutations. | the activity of succinyl-coa:3-ketoacid coa transferase (scot; locus symbol oxct; ec 2.8.3.5) is the main determinant of the ketolytic capacity of tissues. hereditary scot deficiency causes episodic ketoacidosis. here we describe the human scot gene, which spans more than 100 kb and contains 17 exons, on chromosome 5p13. we report pathogenic missense mutations in three scot-deficient patients designated gs04, 05, and 06. gs04 is a g219e/g324e compound; gs05 is a v221m homozygote, and gs06 is a g ... | 2000 | 10964512 |
| aci-1 from acidaminococcus fermentans: characterization of the first beta-lactamase in anaerobic cocci. | acidaminococcus fermentans belongs to the group of strictly anaerobic gram-negative cocci. all previously described acidaminococcus strains are susceptible to beta-lactam antibiotics. an a. fermentans strain (ryc-mr95) resistant to penicillin and expanded-spectrum cephalosporin (amoxicillin and cefotaxime mics, 64 microgram/ml) was isolated from a human perianal abscess. a fragment encoding a beta-lactamase from genomic dna was cloned in escherichia coli k-12 strain hb101, and the recombinant st ... | 2000 | 11036038 |
| complete genome sequence of acidaminococcus fermentans type strain (vr4). | acidaminococcus fermentans (rogosa 1969) is the type species of the genus acidaminococcus, and is of phylogenetic interest because of its isolated placement in a genomically little characterized region of the firmicutes. a. fermentans is known for its habitation of the gastrointestinal tract and its ability to oxidize trans-aconitate. its anaerobic fermentation of glutamate has been intensively studied and will now be complemented by the genomic basis. the strain described in this report is a no ... | 2010 | 21304687 |
| fermentation of 4-aminobutyrate by clostridium aminobutyricum: cloning of two genes involved in the formation and dehydration of 4-hydroxybutyryl-coa. | clostridium aminobutyricum ferments 4-aminobutyrate via succinic semialdehyde, 4-hydroxybutyrate, 4-hydroxybutyryl-coa and crotonyl-coa to acetate and butyrate. the genes coding for the enzymes that catalyse the interconversion of these intermediates are arranged in the order abfd (4-hydroxybutyryl-coa dehydratase), abft (4-hydroxybutyrate coa-transferase), and abfh (nad-dependent 4-hydroxybutyrate dehydrogenase). the genes abfd and abft were cloned, sequenced and expressed as active enzymes in ... | 2000 | 11041350 |
| the iron-sulfur clusters in 2-hydroxyglutaryl-coa dehydratase from acidaminococcus fermentans. biochemical and spectroscopic investigations. | the reversible dehydration of (r)-2-hydroxyglutaryl-coa to (e)-glutaconyl-coa is catalysed by the combined action of two oxygen-sensitive enzymes from acidaminococcus fermentans, the homodimeric component a (2 x 27 kda) and the heterodimeric component d (45 and 50 kda). component a was purified to homogeneity (specific activity 25-30 s-1) using streptavidin-tag affinity chromatography. in the presence of 5 mm mgcl2 and 1 mm adp or atp, component a could be stabilized and stored for 4-5 days at 4 ... | 2000 | 11106419 |
| crystal structure of the acidaminococcus fermentans 2-hydroxyglutaryl-coa dehydratase component a. | acidaminococcus fermentans degrades glutamate via the hydroxyglutarate pathway, which involves the syn-elimination of water from (r)-2-hydroxyglutaryl-coa in a key reaction of the pathway. this anaerobic process is catalyzed by 2-hydroxyglutaryl-coa dehydratase, an enzyme with two components (a and d) that reversibly associate during reaction cycles. component a (compa), a homodimeric protein of 2x27 kda, contains a single, bridging [4fe-4s] cluster and uses the hydrolysis of atp to deliver an e ... | 2001 | 11243821 |
| propionate coa-transferase from clostridium propionicum. cloning of gene and identification of glutamate 324 at the active site. | propionate coa-transferase from clostridium propionicum has been purified and the gene encoding the enzyme has been cloned and sequenced. the enzyme was rapidly and irreversibly inactivated by sodium borohydride or hydroxylamine in the presence of propionyl-coa. the reduction of the thiol ester between a catalytic site glutamate and coa with borohydride and the cleavage by hydroxylamine were used to introduce a site-specific label, which was followed by maldi-tof-ms. this allowed the identificat ... | 2002 | 11784332 |
| adenosine triphosphate-induced electron transfer in 2-hydroxyglutaryl-coa dehydratase from acidaminococcus fermentans. | 2-hydroxyglutaryl-coa dehydratase from acidaminococcus fermentans catalyzes the chemical difficult elimination of water from (r)-2-hydroxyglutaryl-coa to glutaconyl-coa. the enzyme consists of two oxygen-sensitive protein components, the homodimeric activator (a) with one [4fe-4s]1+/2+ cluster and the heterodimeric dehydratase (d) with one nonreducible [4fe-4s]2+ cluster and reduced riboflavin 5'-monophosphate (fmnh2). for activation, atp, mg2+, and a reduced flavodoxin (16 kda) purified from a. ... | 2002 | 11980491 |
| ammonia production by ruminal microorganisms and enumeration, isolation, and characterization of bacteria capable of growth on peptides and amino acids from the sheep rumen. | excessive nh(3) production in the rumen is a major nutritional inefficiency in ruminant animals. experiments were undertaken to compare the rates of nh(3) production from different substrates in ruminal fluid in vitro and to assess the role of asaccharolytic bacteria in nh(3) production. ruminal fluid was taken from four rumen-fistulated sheep receiving a mixed hay-concentrate diet. the calculated rate of nh(3) production from trypticase varied from 1.8 to 19.7 nmol mg of protein(-1) min(-1) dep ... | 2002 | 12324340 |
| on the dehydration of (r)-lactate in the fermentation of alanine to propionate by clostridium propionicum. | all the enzymes of the pathway of (s)-alanine fermentation to acetate and propionate were detected in cell-free extracts of clostridium propionicum . among these (s)-glutamate dehydrogenase (nad), (r)-lactate dehydrogenase (nad) and propionate coa-transferase were purified to apparent homogeneity. their structures were presumably alpha 6, alpha 2 and alpha 4, respectively. the latter enzyme was specific for short-chain monocarboxylic acids with a pronounced preference for (r)-lactate over the (s ... | 1984 | 6586495 |
| covalently linked polyamines in the cell wall peptidoglycan of selenomonas, anaeromusa, dendrosporobacter, acidaminococcus and anaerovibrio belonging to the sporomusa subbranch. | | 2002 | 12469301 |
| diet influences the ecology of lactic acid bacteria and escherichia coli along the digestive tract of cattle: neural networks and 16s rdna. | in this manuscript, the authors have sought to gain a better understanding of the interactions between escherichia coli and lactic acid bacteria (lab) isolated from rogossa mrs agar along the digestive tract of grain- and forage-fed cattle. e. coli from cattle receiving a high-grain diet were more numerous (p<0.05) than from the high-forage diet and the highest numbers were in the faeces. isolates on rogossa mrs agar were always greater in the high-grain diet (p<0.05) and contained a significant ... | 2003 | 12576580 |
| [trans-gram gene transfer: the case of beta-lactamases]. | lateral or horizontal gene transfer is a phenomenon that has influenced the evolution of microorganisms. despite the evolutionary trend toward genetic isolation, lateral transfer seems to take place relatively frequently, bridging the gap between very separate species. the acquisition of foreign genes may have accelerated in recent years because of the increase in the adaptive needs of bacteria, particularly through the use of antibiotics. transfer of genes encoding beta-lactamases from gram-pos ... | 2002 | 12582423 |
| a two [4fe-4s]-cluster-containing ferredoxin as an alternative electron donor for 2-hydroxyglutaryl-coa dehydratase from acidaminococcus fermentans. | the key step in the fermentation of glutamate by acidaminococcus fermentans is a reversible syn-elimination of water from ( r)-2-hydroxyglutaryl-coa to ( e)-glutaconyl-coa catalyzed by 2-hydroxyglutaryl-coa dehydratase, a two-component enzyme system. the actual dehydration is mediated by component d, which contains 1.0 [4fe-4s](2+) cluster, 1.0 reduced riboflavin-5'-phosphate and about 0.1 molybdenum (vi) per heterodimer. the enzyme has to be activated by the extremely oxygen-sensitive [4fe-4s]( ... | 2003 | 12610725 |
| crystal structure of the carboxyltransferase subunit of the bacterial sodium ion pump glutaconyl-coenzyme a decarboxylase. | glutaconyl-coa decarboxylase is a biotin-dependent ion pump whereby the free energy of the glutaconyl-coa decarboxylation to crotonyl-coa drives the electrogenic transport of sodium ions from the cytoplasm into the periplasm. here we present the crystal structure of the decarboxylase subunit (gcdalpha) from acidaminococcus fermentans and its complex with glutaconyl-coa. the active sites of the dimeric gcdalpha lie at the two interfaces between the mono mers, whereas the n-terminal domain provide ... | 2003 | 12853465 |
| a 49 kda microtubule cross-linking protein from artemia franciscana is a coenzyme a-transferase. | embryos and larvae of the brine shrimp, artemia franciscana, were shown previously to possess a protein, now termed p49, which cross-links microtubules in vitro. molecular characteristics of p49 were described, but the protein's identity and its role in the cell were not determined. degenerate oligonucleotide primers designed on the basis of peptide sequence obtained by edman degradation during this study were used to generate p49 cdnas by rt-pcr and these were cloned and sequenced. comparison w ... | 2003 | 14653822 |
| dehydration of (r)-2-hydroxyacyl-coa to enoyl-coa in the fermentation of alpha-amino acids by anaerobic bacteria. | several clostridia and fusobacteria ferment alpha-amino acids via (r)-2-hydroxyacyl-coa, which is dehydrated to enoyl-coa by syn-elimination. this reaction is of great mechanistic interest, since the beta-hydrogen, to be eliminated as proton, is not activated (pk 40-50). a mechanism has been proposed, in which one high-energy electron acts as cofactor and transiently reduces the electrophilic thiol ester carbonyl to a nucleophilic ketyl radical anion. the 2-hydroxyacyl-coa dehydratases are two-c ... | 2004 | 15374661 |
| glutaconate coa-transferase from acidaminococcus fermentans: the crystal structure reveals homology with other coa-transferases. | coenzyme a-transferases are a family of enzymes with a diverse substrate specificity and subunit composition. members of this group of enzymes are found in anaerobic fermenting bacteria, aerobic bacteria and in the mitochondria of humans and other mammals, but so far none have been crystallized. a defect in the human gene encoding succinyl-coa: 3-oxoacid coa-transferase causes a metabolic disease which leads to severe ketoacidosis, thus reflecting the importance of this family of enzymes. all co ... | 1997 | 9083111 |
| conversion of glutaconate coa-transferase from acidaminococcus fermentans into an acyl-coa hydrolase by site-directed mutagenesis. | the heterooctameric (alphabeta)4 glutaconate coa-transferase (ec 2.8.3.12) from the anaerobic bacterium acidaminococcus fermentans catalyses the transfer of coash from acetyl-coa to the 1-carboxylate of glutaconate. during this reaction the glutamate residue 54 of the beta-subunit (betae54) forms a coa-ester. the single amino acid replacement betae54d resulted in a drastic change of enzymatic function. the coa-transferase activity decreased from 140 to less than 0.01 s(-1), whereas the acyl-coa ... | 1997 | 9089292 |
| genes coding for the benzoyl-coa pathway of anaerobic aromatic metabolism in the bacterium thauera aromatica. | many aromatic compounds are anaerobically oxidized to co2 via benzoyl-coa as the common aromatic intermediate. in thauera aromatica, the central benzoyl-coa pathway comprises the atp-driven two-electron reduction of the benzene ring; this reaction uses a ferredoxin as electron donor and is catalyzed by benzoyl-coa reductase. the first intermediate, cyclohex-1,5-diene-1-carboxyl-coa, is subsequently hydrated by dienoyl-coa hydratase to 6-hydroxycyclohex-1-ene-1-carboxyl-coa. formation of the main ... | 1998 | 9746358 |
| the sodium ion translocating glutaconyl-coa decarboxylase from acidaminococcus fermentans: cloning and function of the genes forming a second operon. | glutaconyl-coa decarboxylase from acidaminococcus fermentans (clostridal cluster ix), a strict anaerobic inhabitant of animal intestines, uses the free energy of decarboxylation (delta g(o) approximately -30 kj mol-1) in order to translocate na+ from the inside through the cytoplasmic membrane. the proton, which is required for decarboxylation, most probably comes from the outside. the enzyme consists of four different subunits. the largest subunit, alpha or gcda (65 kda), catalyses the transfer ... | 1999 | 10027965 |
| acidaminococcus intestini sp. nov., isolated from human clinical samples. | eleven strains of a hitherto unknown, gram-negative, anaerobic coccus were recovered from various human clinical samples of patients hospitalized in two geographically distant french hospitals. these strains displayed the morphology and growth characteristics of those related to the genus acidaminococcus. the clinical isolates shared at least 99.9 and 99.7 % of their nucleotide positions in the 16s and 23s rrna gene sequences, respectively. they displayed 95.6 and 88.9 % 16s and 23s rrna gene se ... | 2007 | 17911303 |
| spectroscopic evidence for an all-ferrous [4fe-4s]0 cluster in the superreduced activator of 2-hydroxyglutaryl-coa dehydratase from acidaminococcus fermentans. | the key enzyme of the fermentation of glutamate by acidaminococcus fermentans, 2-hydroxyglutaryl-coenzyme a dehydratase, catalyzes the reversible syn-elimination of water from (r)-2-hydroxyglutaryl-coenzyme a, resulting in (e)-glutaconylcoenzyme a. the dehydratase system consists of two oxygen-sensitive protein components, the activator (hgdc) and the actual dehydratase (hgdab). previous biochemical and spectroscopic studies revealed that the reduced [4fe-4s]+ cluster containing activator transf ... | 2008 | 18274792 |
| evaluation of the bacterial diversity in the feces of cattle using 16s rdna bacterial tag-encoded flx amplicon pyrosequencing (btefap). | the microbiota of an animal's intestinal tract plays important roles in the animal's overall health, productivity and well-being. there is still a scarcity of information on the microbial diversity in the gut of livestock species such as cattle. the primary reason for this lack of data relates to the expense of methods needed to generate such data. here we have utilized a bacterial tag-encoded flx 16s rdna amplicon pyrosequencing (btefap) approach that is able to perform diversity analyses of ga ... | 2008 | 18652685 |
| an asymmetric model for na+-translocating glutaconyl-coa decarboxylases. | glutaconyl-coa decarboxylase (gcd) couples the biotin-dependent decarboxylation of glutaconyl-coa with the generation of an electrochemical na(+) gradient. sequencing of the genes encoding all subunits of the clostridium symbiosum decarboxylase membrane complex revealed that it comprises two distinct biotin carrier subunits, gcdc(1) and gcdc(2), which differ in the length of a central alanine- and proline-rich linker domain. co-crystallization of the decarboxylase subunit gcda with the substrate ... | 2009 | 19654317 |
| exposure of different bacterial inocula to newborn chicken affects gut microbiota development and ileum gene expression. | the transition from a sterile gut environment to the development of microbiota in the newborns is not fully understood. the objective of this study was to investigate the impact of exposure to bacterial communities on the development of gut microbiota in the newly hatched chicken. a total of 90 as-hatched chicks were divided into three groups. groups a and b were treated with inocula of the cecal origin, whereas group c was fed with sterile water. the major bacteria in inoculum-i to treat group ... | 2010 | 19956274 |
| substrate specificity of 2-hydroxyglutaryl-coa dehydratase from clostridium symbiosum: toward a bio-based production of adipic acid. | expression of six genes from two glutamate fermenting clostridia converted escherichia coli into a producer of glutaconate from 2-oxoglutarate of the general metabolism (djurdjevic, i. et al. 2010, appl. environ. microbiol.77, 320-322). the present work examines whether this pathway can also be used to reduce 2-oxoadipate to (r)-2-hydroxyadipic acid and dehydrate its coa thioester to 2-hexenedioic acid, an unsaturated precursor of the biotechnologically valuable adipic acid (hexanedioic acid). 2 ... | 2011 | 21434666 |
| Complete Genome Sequence of Acidaminococcus intestini RYC-MR95, a Gram-Negative Bacterium from the Phylum Firmicutes. | Acidaminococcus intestini belongs to the family Acidaminococcaceae, order Selenomonadales, class Negativicutes, phylum Firmicutes. Negativicutes show the double-membrane system of Gram-negative bacteria, although their chromosomal backbone is closely related to that of Gram-positive bacteria of the phylum Firmicutes. The complete genome of a clinical A. intestini strain is here presented. | 2011 | 22123762 |
| dual mechanisms of tricarboxylate transport and catabolism by acidaminococcus fermentans. | acidaminococcus fermentans utilized citrate or the citrate analog aconitate as an energy source for growth, and these tricarboxylates were used simultaneously. citrate utilization and uptake showed biphasic kinetics. high-affinity citrate uptake had a k(t) of 40 mum, but the v(max) was only 25 nmol/mg of protein per min. low-affinity citrate utilization had a 10-fold higher v(max), but the k(s) was greater than 1.0 mm. aconitate was a competitive inhibitor (k(i) = 34mum) of high-affinity citrate ... | 1994 | 16349331 |
| sodium ion pumps and hydrogen production in glutamate fermenting anaerobic bacteria. | anaerobic bacteria ferment glutamate via two different pathways to ammonia, carbon dioxide, acetate, butyrate and molecular hydrogen. the coenzyme b12-dependent pathway in clostridium tetanomorphum via 3-methylaspartate involves pyruvate:ferredoxin oxidoreductase and a novel enzyme, a membrane-bound nadh:ferredoxin oxidoreductase. the flavin- and iron-sulfur-containing enzyme probably uses the energy difference between reduced ferredoxin and nadh to generate an electrochemical na+ gradient, whic ... | 2005 | 16645308 |